1
|
Sammut MJ, Dotzert MS, Melling CWJ. Mechanisms of insulin resistance in type 1 diabetes mellitus: A case of glucolipotoxicity in skeletal muscle. J Cell Physiol 2024:e31419. [PMID: 39192756 DOI: 10.1002/jcp.31419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2024] [Revised: 07/16/2024] [Accepted: 08/09/2024] [Indexed: 08/29/2024]
Abstract
Insulin resistance (IR), a hallmark of type 2 diabetes mellitus, develops in a significant number of patients with type 1 diabetes mellitus (T1DM) despite the use of insulin therapy to control glycemia. However, little is currently understood regarding the underlying mechanisms of IR in T1DM, especially within the context of chronic insulin treatment. Recent evidence suggests an important influence of glucolipotoxicity in skeletal muscle on insulin sensitivity in T1DM. Thus, this review summarizes our current knowledge regarding impairments in skeletal muscle lipid, glucose, and oxidative metabolism in the development of IR in insulin-treated T1DM.
Collapse
Affiliation(s)
- Mitchell J Sammut
- School of Kinesiology, Faculty of Health Sciences, Western University, London, Ontario, Canada
| | - Michelle S Dotzert
- School of Kinesiology, Faculty of Health Sciences, Western University, London, Ontario, Canada
| | - C W James Melling
- School of Kinesiology, Faculty of Health Sciences, Western University, London, Ontario, Canada
- Department of Physiology & Pharmacology, Schulich School of Medicine & Dentistry, Western University, London, Ontario, Canada
| |
Collapse
|
2
|
Elkanawati RY, Sumiwi SA, Levita J. Impact of Lipids on Insulin Resistance: Insights from Human and Animal Studies. Drug Des Devel Ther 2024; 18:3337-3360. [PMID: 39100221 PMCID: PMC11298177 DOI: 10.2147/dddt.s468147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2024] [Accepted: 07/24/2024] [Indexed: 08/06/2024] Open
Abstract
Insulin resistance (IR) is a complex pathological condition central to metabolic diseases such as type 2 diabetes mellitus (T2DM), cardiovascular disease, non-alcoholic fatty liver disease, and polycystic ovary syndrome (PCOS). This review evaluates the impact of lipids on insulin resistance (IR) by analyzing findings from human and animal studies. The articles were searched on the PubMed database using two keywords: (1) "Role of Lipids AND Insulin Resistance AND Humans" and (2) "Role of Lipids AND Insulin Resistance AND Animal Models". Studies in humans revealed that elevated levels of free fatty acids (FFAs) and triglycerides (TGs) are closely associated with reduced insulin sensitivity, and interventions like metformin and omega-3 fatty acids show potential benefits. In animal models, high-fat diets disrupt insulin signaling and increase inflammation, with lipid mediators such as diacylglycerol (DAG) and ceramides playing significant roles. DAG activates protein kinase C, which eventually impairs insulin signaling, while ceramides inhibit Akt/PKB, further contributing to IR. Understanding these mechanisms is crucial for developing effective prevention and treatment strategies for IR-related diseases.
Collapse
Affiliation(s)
- Rani Yulifah Elkanawati
- Master Program in Pharmacy, Faculty of Pharmacy, Padjadjaran University, Jawa Barat, West Java, 45363, Indonesia
| | - Sri Adi Sumiwi
- Department of Pharmacology and Clinical Pharmacy, Faculty of Pharmacy, Padjadjaran University, Sumedang, West Java, 45363, Indonesia
| | - Jutti Levita
- Department of Pharmacology and Clinical Pharmacy, Faculty of Pharmacy, Padjadjaran University, Sumedang, West Java, 45363, Indonesia
| |
Collapse
|
3
|
Miazga K, Kopczyńska K, Szaluś-Jordanow O, Moroz-Fik A, Wilczak J, Barszcz K, Cywińska A. Metabolomic analysis indicated changes in triacylglycerols' levels as a result of training in Whippet dogs. Sci Rep 2023; 13:18223. [PMID: 37880383 PMCID: PMC10600122 DOI: 10.1038/s41598-023-45546-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 10/20/2023] [Indexed: 10/27/2023] Open
Abstract
Regular physical effort produces metabolic changes manifested as adaptation to exercise and increasing performance. In humans these changes have been characterized at metabolome level as depending on the discipline. However, all sports involve some level of changes in protein, carbohydrate and lipid metabolism. Recently, also performance horses have been subjected to metabolic analyses, but similar studies were lacking in sports dogs. In this study we performed the metabolomic analysis in plasma of Whippet dogs regularly trained and competing in coursing events, and untrained dogs of the same breed, fed with the same diet. We have also compared the hematological and blood biochemical results in these two groups of dogs. Basic blood tests indicated that enzymes related to lipid metabolism (lipase and gamma-glutamyltransferase) differed considerably between the groups. Metabolomic analysis of plasma confirmed the metabolic shift expressed as the differences in triacylglycerols levels between training and non-training dogs, aimed at improving the use of fatty acids as a source of energy during exertion. Surprisingly, other classes of metabolites were only hardly changed when comparing training and non-training Whippets.
Collapse
Affiliation(s)
- Katarzyna Miazga
- Department of Pathology and Veterinary Diagnostics, Institute of Veterinary Medicine, Warsaw University of Life Sciences-SGGW, Nowoursynowska 159C, 02-776, Warsaw, Poland
- Municipal Zoological Garden in Warsaw, Ratuszowa 1/3, 03-461, Warsaw, Poland
| | - Klaudia Kopczyńska
- Department of Functional and Organic Food, Institute of Human Nutrition Sciences, Warsaw University of Life Sciences, 02-776, Warsaw, Poland
| | - Olga Szaluś-Jordanow
- Department of Small Animal Diseases with Clinic, Institute of Veterinary Medicine, Warsaw University of Life Sciences-SGGW, Nowoursynowska 159C, 02-776, Warsaw, Poland
| | - Agata Moroz-Fik
- Division of Veterinary Epidemiology and Economics, Institute of Veterinary Medicine, Warsaw University of Life Sciences-SGGW, Nowoursynowska 159C, 02-776, Warsaw, Poland
| | - Jacek Wilczak
- Department of Physiology, Institute of Veterinary Medicine, Warsaw University of Life Sciences-SGGW, Nowoursynowska 159C, 02-776, Warsaw, Poland
| | - Karolina Barszcz
- Department of Morphological Sciences, Warsaw University of Life Sciences, Nowoursynowska 159C, 02-776, Warsaw, Poland.
| | - Anna Cywińska
- Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University in Torun, Lwowska 1, 87-100, Torun, Poland.
| |
Collapse
|
4
|
Gu H, Zhou Y, Yang J, Li J, Peng Y, Zhang X, Miao Y, Jiang W, Bu G, Hou L, Li T, Zhang L, Xia X, Ma Z, Xiong Y, Zuo B. Targeted overexpression of PPARγ in skeletal muscle by random insertion and CRISPR/Cas9 transgenic pig cloning enhances oxidative fiber formation and intramuscular fat deposition. FASEB J 2021; 35:e21308. [PMID: 33481304 DOI: 10.1096/fj.202001812rr] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2020] [Revised: 12/08/2020] [Accepted: 12/11/2020] [Indexed: 11/11/2022]
Abstract
Peroxisome proliferator-activated receptor gamma (PPARγ) is a master regulator of adipogenesis and lipogenesis. To understand its roles in fiber formation and fat deposition in skeletal muscle, we successfully generated muscle-specific overexpression of PPARγ in two pig models by random insertion and CRISPR/Cas9 transgenic cloning procedures. The content of intramuscular fat was significantly increased in PPARγ pigs while had no changes on lean meat ratio. PPARγ could promote adipocyte differentiation by activating adipocyte differentiating regulators such as FABP4 and CCAAT/enhancer-binding protein (C/EBP), along with enhanced expression of LPL, FABP4, and PLIN1 to proceed fat deposition. Proteomics analyses demonstrated that oxidative metabolism of fatty acids and respiratory chain were activated in PPARγ pigs, thus, gathered more Ca2+ in PPARγ pigs. Raising of Ca2+ could result in increased phosphorylation of CAMKII and p38 MAPK in PPARγ pigs, which can stimulate MEF2 and PGC1α to affect fiber type and oxidative capacity. These results support that skeletal muscle-specific overexpression of PPARγ can promote oxidative fiber formation and intramuscular fat deposition in pigs.
Collapse
Affiliation(s)
- Hao Gu
- Key Laboratory of Swine Genetics and Breeding of Ministry of Agriculture and Rural Affairs & Key Laboratory of Agriculture Animal Genetics, Breeding and Reproduction of Ministry of Education, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan, P.R. China
| | - Ying Zhou
- Key Laboratory of Swine Genetics and Breeding of Ministry of Agriculture and Rural Affairs & Key Laboratory of Agriculture Animal Genetics, Breeding and Reproduction of Ministry of Education, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan, P.R. China
| | - Jinzeng Yang
- Department of Human Nutrition, Food and Animal Sciences, University of Hawaii at Manoa, Honolulu, HI, USA
| | - Jianan Li
- Key Laboratory of Swine Genetics and Breeding of Ministry of Agriculture and Rural Affairs & Key Laboratory of Agriculture Animal Genetics, Breeding and Reproduction of Ministry of Education, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan, P.R. China
| | - Yaxin Peng
- Key Laboratory of Swine Genetics and Breeding of Ministry of Agriculture and Rural Affairs & Key Laboratory of Agriculture Animal Genetics, Breeding and Reproduction of Ministry of Education, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan, P.R. China
| | - Xia Zhang
- Key Laboratory of Swine Genetics and Breeding of Ministry of Agriculture and Rural Affairs & Key Laboratory of Agriculture Animal Genetics, Breeding and Reproduction of Ministry of Education, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan, P.R. China
| | - Yiliang Miao
- Key Laboratory of Swine Genetics and Breeding of Ministry of Agriculture and Rural Affairs & Key Laboratory of Agriculture Animal Genetics, Breeding and Reproduction of Ministry of Education, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan, P.R. China
| | - Wei Jiang
- Key Laboratory of Swine Genetics and Breeding of Ministry of Agriculture and Rural Affairs & Key Laboratory of Agriculture Animal Genetics, Breeding and Reproduction of Ministry of Education, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan, P.R. China
| | - Guowei Bu
- Key Laboratory of Swine Genetics and Breeding of Ministry of Agriculture and Rural Affairs & Key Laboratory of Agriculture Animal Genetics, Breeding and Reproduction of Ministry of Education, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan, P.R. China
| | - Liming Hou
- Key Laboratory of Swine Genetics and Breeding of Ministry of Agriculture and Rural Affairs & Key Laboratory of Agriculture Animal Genetics, Breeding and Reproduction of Ministry of Education, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan, P.R. China
| | - Ting Li
- Key Laboratory of Swine Genetics and Breeding of Ministry of Agriculture and Rural Affairs & Key Laboratory of Agriculture Animal Genetics, Breeding and Reproduction of Ministry of Education, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan, P.R. China
| | - Lin Zhang
- Key Laboratory of Swine Genetics and Breeding of Ministry of Agriculture and Rural Affairs & Key Laboratory of Agriculture Animal Genetics, Breeding and Reproduction of Ministry of Education, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan, P.R. China
| | - Xiaoliang Xia
- Key Laboratory of Swine Genetics and Breeding of Ministry of Agriculture and Rural Affairs & Key Laboratory of Agriculture Animal Genetics, Breeding and Reproduction of Ministry of Education, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan, P.R. China
| | - Zhiyuan Ma
- Key Laboratory of Swine Genetics and Breeding of Ministry of Agriculture and Rural Affairs & Key Laboratory of Agriculture Animal Genetics, Breeding and Reproduction of Ministry of Education, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan, P.R. China
| | - Yuanzhu Xiong
- Key Laboratory of Swine Genetics and Breeding of Ministry of Agriculture and Rural Affairs & Key Laboratory of Agriculture Animal Genetics, Breeding and Reproduction of Ministry of Education, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan, P.R. China
| | - Bo Zuo
- Key Laboratory of Swine Genetics and Breeding of Ministry of Agriculture and Rural Affairs & Key Laboratory of Agriculture Animal Genetics, Breeding and Reproduction of Ministry of Education, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan, P.R. China
| |
Collapse
|
5
|
Ferrara PJ, Rong X, Maschek JA, Verkerke AR, Siripoksup P, Song H, Green TD, Krishnan KC, Johnson JM, Turk J, Houmard JA, Lusis AJ, Drummond MJ, McClung JM, Cox JE, Shaikh SR, Tontonoz P, Holland WL, Funai K. Lysophospholipid acylation modulates plasma membrane lipid organization and insulin sensitivity in skeletal muscle. J Clin Invest 2021; 131:135963. [PMID: 33591957 DOI: 10.1172/jci135963] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 02/11/2021] [Indexed: 01/09/2023] Open
Abstract
Aberrant lipid metabolism promotes the development of skeletal muscle insulin resistance, but the exact identity of lipid-mediated mechanisms relevant to human obesity remains unclear. A comprehensive lipidomic analysis of primary myocytes from individuals who were insulin-sensitive and lean (LN) or insulin-resistant with obesity (OB) revealed several species of lysophospholipids (lyso-PLs) that were differentially abundant. These changes coincided with greater expression of lysophosphatidylcholine acyltransferase 3 (LPCAT3), an enzyme involved in phospholipid transacylation (Lands cycle). Strikingly, mice with skeletal muscle-specific knockout of LPCAT3 (LPCAT3-MKO) exhibited greater muscle lysophosphatidylcholine/phosphatidylcholine, concomitant with improved skeletal muscle insulin sensitivity. Conversely, skeletal muscle-specific overexpression of LPCAT3 (LPCAT3-MKI) promoted glucose intolerance. The absence of LPCAT3 reduced phospholipid packing of cellular membranes and increased plasma membrane lipid clustering, suggesting that LPCAT3 affects insulin receptor phosphorylation by modulating plasma membrane lipid organization. In conclusion, obesity accelerates the skeletal muscle Lands cycle, whose consequence might induce the disruption of plasma membrane organization that suppresses muscle insulin action.
Collapse
Affiliation(s)
- Patrick J Ferrara
- Diabetes and Metabolism Research Center and.,Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah, USA.,East Carolina Diabetes and Obesity Institute and.,Human Performance Laboratory, East Carolina University, Greenville, North Carolina, USA.,Molecular Medicine Program, University of Utah, Salt Lake City, Utah, USA
| | - Xin Rong
- Department of Pathology and Laboratory Medicine, UCLA, Los Angeles, California, USA
| | - J Alan Maschek
- Diabetes and Metabolism Research Center and.,Metabolomics, Mass Spectrometry, and Proteomics Core and
| | - Anthony Rp Verkerke
- Diabetes and Metabolism Research Center and.,Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah, USA.,East Carolina Diabetes and Obesity Institute and.,Human Performance Laboratory, East Carolina University, Greenville, North Carolina, USA
| | - Piyarat Siripoksup
- Diabetes and Metabolism Research Center and.,Department of Physical Therapy and Athletic Training, University of Utah, Salt Lake City, Utah, USA
| | - Haowei Song
- Division of Endocrinology Metabolism and Lipid Research, School of Medicine, Washington University in St. Louis, St. Louis, Missouri, USA
| | | | | | - Jordan M Johnson
- Diabetes and Metabolism Research Center and.,Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah, USA.,East Carolina Diabetes and Obesity Institute and.,Human Performance Laboratory, East Carolina University, Greenville, North Carolina, USA
| | - John Turk
- Division of Endocrinology Metabolism and Lipid Research, School of Medicine, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Joseph A Houmard
- East Carolina Diabetes and Obesity Institute and.,Human Performance Laboratory, East Carolina University, Greenville, North Carolina, USA
| | - Aldons J Lusis
- Cardiology Division, Department of Medicine, UCLA, Los Angeles, California, USA
| | - Micah J Drummond
- Diabetes and Metabolism Research Center and.,Molecular Medicine Program, University of Utah, Salt Lake City, Utah, USA.,Department of Physical Therapy and Athletic Training, University of Utah, Salt Lake City, Utah, USA
| | | | - James E Cox
- Diabetes and Metabolism Research Center and.,Metabolomics, Mass Spectrometry, and Proteomics Core and.,Department of Biochemistry, University of Utah, Salt Lake City, Utah, USA
| | - Saame Raza Shaikh
- East Carolina Diabetes and Obesity Institute and.,Department of Nutrition, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Peter Tontonoz
- Department of Pathology and Laboratory Medicine, UCLA, Los Angeles, California, USA
| | - William L Holland
- Diabetes and Metabolism Research Center and.,Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah, USA.,Molecular Medicine Program, University of Utah, Salt Lake City, Utah, USA
| | - Katsuhiko Funai
- Diabetes and Metabolism Research Center and.,Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah, USA.,East Carolina Diabetes and Obesity Institute and.,Human Performance Laboratory, East Carolina University, Greenville, North Carolina, USA.,Molecular Medicine Program, University of Utah, Salt Lake City, Utah, USA.,Department of Physical Therapy and Athletic Training, University of Utah, Salt Lake City, Utah, USA
| |
Collapse
|
6
|
Kahn D, Perreault L, Macias E, Zarini S, Newsom SA, Strauss A, Kerege A, Harrison K, Snell-Bergeon J, Bergman BC. Subcellular localisation and composition of intramuscular triacylglycerol influence insulin sensitivity in humans. Diabetologia 2021; 64:168-180. [PMID: 33128577 PMCID: PMC7718332 DOI: 10.1007/s00125-020-05315-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 08/25/2020] [Indexed: 12/25/2022]
Abstract
AIMS/HYPOTHESIS Subcellular localisation is an important factor in the known impact of bioactive lipids, such as diacylglycerol and sphingolipids, on insulin sensitivity in skeletal muscle; yet, the role of localised intramuscular triacylglycerol (IMTG) is yet to be described. Excess accumulation of IMTG in skeletal muscle is associated with insulin resistance, and we hypothesised that differences in subcellular localisation and composition of IMTG would relate to metabolic health status in humans. METHODS We evaluated subcellular localisation of IMTG in lean participants, endurance-trained athletes, individuals with obesity and individuals with type 2 diabetes using LC-MS/MS of fractionated muscle biopsies and insulin clamps. RESULTS Insulin sensitivity was significantly different between each group (athletes>lean>obese>type 2 diabetes; p < 0.001). Sarcolemmal IMTG was significantly greater in individuals with obesity and type 2 diabetes compared with lean control participants and athletes, but individuals with type 2 diabetes were the only group with significantly increased saturated IMTG. Sarcolemmal IMTG was inversely related to insulin sensitivity. Nuclear IMTG was significantly greater in individuals with type 2 diabetes compared with lean control participants and athletes, and total and saturated IMTG localised in the nucleus had a significant inverse relationship with insulin sensitivity. Total cytosolic IMTG was not different between groups, but saturated cytosolic IMTG species were significantly increased in individuals with type 2 diabetes compared with all other groups. There were no significant differences between groups for IMTG concentration in the mitochondria/endoplasmic reticulum. CONCLUSIONS/INTERPRETATION These data reveal previously unknown differences in subcellular IMTG localisation based on metabolic health status and indicate the influence of sarcolemmal and nuclear IMTG on insulin sensitivity. Additionally, these studies suggest saturated IMTG may be uniquely deleterious for muscle insulin sensitivity. Graphical abstract.
Collapse
Affiliation(s)
- Darcy Kahn
- Division of Endocrinology, Metabolism, and Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Leigh Perreault
- Division of Endocrinology, Metabolism, and Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Emily Macias
- Division of Endocrinology, Metabolism, and Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Simona Zarini
- Division of Endocrinology, Metabolism, and Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | | | - Allison Strauss
- Division of Endocrinology, Metabolism, and Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Anna Kerege
- Division of Endocrinology, Metabolism, and Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Kathleen Harrison
- Division of Endocrinology, Metabolism, and Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Janet Snell-Bergeon
- Division of Endocrinology, Metabolism, and Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Bryan C Bergman
- Division of Endocrinology, Metabolism, and Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
| |
Collapse
|
7
|
Daemen S, Gemmink A, Paul A, Billecke N, Rieger K, Parekh SH, Hesselink MKC. Label-free CARS microscopy reveals similar triacylglycerol acyl chain length and saturation in myocellular lipid droplets of athletes and individuals with type 2 diabetes. Diabetologia 2020; 63:2654-2664. [PMID: 32880685 PMCID: PMC7641925 DOI: 10.1007/s00125-020-05266-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Accepted: 07/17/2020] [Indexed: 01/17/2023]
Abstract
AIMS/HYPOTHESIS Intramyocellular lipid (IMCL) content associates with development of insulin resistance, albeit not in insulin-sensitive endurance-trained athletes (trained). Qualitative and spatial differences in muscle lipid composition may underlie this so-called athlete's paradox. Here we studied triacylglycerol (TAG) composition of individual myocellular lipid droplets (LDs) in trained individuals and individuals with type 2 diabetes mellitus. METHODS Trained ([Formula: see text] 71.0 ± 1.6 ml O2 [kg lean body mass (LBM)]-1 min-1), normoglycaemic (fasting glucose 5.1 ± 0.1 mmol/l) individuals and untrained ([Formula: see text] 36.8 ± 1.5 ml O2 [kg LBM]-1 min-1) individuals with type 2 diabetes (fasting glucose 7.4 ± 0.5 mmol/l), with similar IMCL content (3.5 ± 0.7% vs 2.5 ± 0.3%, p = 0.241), but at opposite ends of the insulin sensitivity spectrum (glucose infusion rate 93.8 ± 6.6 vs 25.7 ± 5.3 μmol [kg LBM]-1 min-1 for trained individuals and those with type 2 diabetes, respectively) were included from our database in the present study. We applied in situ label-free broadband coherent anti-Stokes Raman scattering (CARS) microscopy to sections from skeletal muscle biopsies to measure TAG acyl chain length and saturation of myocellular LDs. This approach uniquely permits examination of individual LDs in their native environment, in a fibre-type-specific manner, taking into account LD size and subcellular location. RESULTS Despite a significant difference in insulin sensitivity, we observed remarkably similar acyl chain length and saturation in trained and type 2 diabetic individuals (chain length: 18.12 ± 0.61 vs 18.36 ± 0.43 number of carbons; saturation: 0.37 ± 0.05 vs 0.38 ± 0.06 number of C=C bonds). Longer acyl chains or higher saturation (lower C=C number) could be detected in subpopulations of LDs, i.e. large LDs (chain length: 18.11 ± 0.48 vs 18.63 ± 0.57 carbon number) and subsarcolemmal LDs (saturation: 0.34 ± 0.02 vs 0.36 ± 0.04 C=C number), which are more abundant in individuals with type 2 diabetes. CONCLUSIONS/INTERPRETATION In contrast to reports of profound differences in the lipid composition of lipids extracted from skeletal muscle from trained and type 2 diabetic individuals, our in situ, LD-specific approach detected only modest differences in TAG composition in LD subpopulations, which were dependent on LD size and subcellular location. If, and to what extent, these modest differences can impact insulin sensitivity remains to be elucidated. Graphical abstract.
Collapse
Affiliation(s)
- Sabine Daemen
- Department of Nutrition and Movement Sciences, NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre+, Maastricht, the Netherlands
| | - Anne Gemmink
- Department of Nutrition and Movement Sciences, NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre+, Maastricht, the Netherlands
| | - Alexandra Paul
- Department of Biology and Biological Engineering, Division of Chemical Biology, Chalmers University of Technology, Gothenburg, Sweden
- Department of Biomedical Engineering, University of Texas at Austin, Austin, TX, USA
| | - Nils Billecke
- Department of Molecular Spectroscopy, Max Planck Institute for Polymer Research, Mainz, Germany
| | - Katrina Rieger
- Department of Molecular Spectroscopy, Max Planck Institute for Polymer Research, Mainz, Germany
| | - Sapun H Parekh
- Department of Biomedical Engineering, University of Texas at Austin, Austin, TX, USA.
- Department of Molecular Spectroscopy, Max Planck Institute for Polymer Research, Mainz, Germany.
| | - Matthijs K C Hesselink
- Department of Nutrition and Movement Sciences, NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre+, Maastricht, the Netherlands.
| |
Collapse
|
8
|
MR spectroscopy differences between lipomatosis of nerve and neuromuscular choristoma: a potential adjunctive diagnostic tool. Skeletal Radiol 2020; 49:2051-2057. [PMID: 32535774 DOI: 10.1007/s00256-020-03479-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 05/18/2020] [Accepted: 05/19/2020] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To describe differences between lipomatosis of nerve (LN) and neuromuscular choristoma (NMC) evaluated with MR spectroscopy (MRS). MATERIALS AND METHODS Eight patients were included in this prospective pilot study: three patients with LNs and five with NMCs. Single voxel PRESS MRS of the tumors were acquired with 3 T MRI. MRS data were processed with LCModel version 6.3-1J using the internal "lipid-8" basis set. From individual lipid peak and water content measurements, total fatty acid molecules (TFAM), unsaturated fatty acid molecules (UFAM), and glycerol molecules (GM) were computed and analyzed, as well as ratios of UFAM/TFAM, TFAM/GM, and a fatty-acid chain-length index (CLI). RESULTS The LN group included two men and one woman (average age 58.3 years); the NMC group included two men and three women (average age 20.4 years). Lipid composition analysis showed that LN had considerably more fat than NMC: TFAM: LN = 15.29 vs NMC = 7.14; UFAM: LN = 4.48 vs NMC = 2.63; GM: LN = 5.20 vs NMC = 1.02. Both tumors had a similar fraction of unsaturated fatty acids: UFAM/TFAM: LN = 0.29 vs NMC = 0.37. LN had the usual number of FA molecules/glycerol molecule, while NMC had considerably more: TFAM/GM: LN = 2.94 vs NMC = 6.98. Finally, average FA chains were longer in NMC: CLI: LN = 17.39 vs NMC = 22.55. CONCLUSION Our analysis suggests measurable differences in the amount and composition of lipid in LN and NMC. While a larger, statistically powered study is needed, these initial findings may be helpful to properly diagnose ambiguous cases and thereby avoid surgical intervention such as biopsy.
Collapse
|
9
|
Xu D, Liu L, Zhao Y, Yang L, Cheng J, Hua R, Zhang Z, Li Q. Melatonin protects mouse testes from palmitic acid-induced lipotoxicity by attenuating oxidative stress and DNA damage in a SIRT1-dependent manner. J Pineal Res 2020; 69:e12690. [PMID: 32761924 DOI: 10.1111/jpi.12690] [Citation(s) in RCA: 110] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 07/23/2020] [Accepted: 08/01/2020] [Indexed: 12/13/2022]
Abstract
Palmitic acid (PA), the main component of dietary saturated fat, has been known to increase in patients with obesity, and PA-induced lipotoxicity may contribute to obesity-related male infertility. Melatonin has beneficial effects on reproductive processes; however, the effect and the underlying molecular mechanism of melatonin's involvement in PA-induced cytotoxicity in the testes are poorly understood. Our findings showed that lipotoxicity was observed in mouse testes after long-term PA treatment and that melatonin therapy restored spermatogenesis and fertility in these males. Moreover, melatonin therapy suppressed PA-induced apoptosis by modulating apoptosis-associated proteins such as Bcl2, Bax, C-Caspase3, C-Caspase12, and CHOP in type B spermatogonial stem cells. Changes in the expression of endoplasmic reticulum (ER) stress markers (p-IRE1, p-PERK, ATF4) and intracellular Ca2+ levels showed that melatonin relieved PA-induced ER stress. Mechanistically, melatonin stimulated the expression and nuclear translocation of SIRT1 through its receptors and prevented PA-induced ROS production and mitochondrial dysfunction via SIRT1 signaling pathway. Furthermore, melatonin promoted SIRT1-mediated p53 deacetylation, thereby relieving G2/M arrest in response to PA-stimulated DNA damage. Collectively, these findings indicate that melatonin protects the testes from PA-induced lipotoxicity through the activation of SIRT1, which alleviates oxidative stress, ER stress, mitochondrial dysfunction, and DNA damage.
Collapse
Affiliation(s)
- Dejun Xu
- College of Animal Science and Technology, Southwest University, Chongqing, China
- College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Lingbin Liu
- College of Animal Science and Technology, Southwest University, Chongqing, China
| | - Yongju Zhao
- College of Animal Science and Technology, Southwest University, Chongqing, China
| | - Li Yang
- College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Jianyong Cheng
- College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Rongmao Hua
- College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Zelin Zhang
- College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Qingwang Li
- College of Animal Science and Technology, Northwest A&F University, Yangling, China
| |
Collapse
|
10
|
Yan Q, Huang H, Lu S, Ou B, Feng J, Shan W, Li H, Wang Z, Hong A, Ma Y. PACAP ameliorates fertility in obese male mice via PKA/CREB pathway‐dependent Sirt1 activation and p53 deacetylation. J Cell Physiol 2020; 235:7465-7483. [DOI: 10.1002/jcp.29651] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Accepted: 02/04/2020] [Indexed: 01/07/2023]
Affiliation(s)
- Qiuxia Yan
- Department of Cellular BiologyInstitute of BiomedicineNational Engineering Research Center of Genetic Medicine, Key Laboratory of Bioengineering Medicine of Guangdong Province, Jinan UniversityGuangzhou China
- Center for Reproductive Medicine, The Sixth Affiliated Hospital of Guangzhou Medical University, Qingyuan People's HospitalQingyuan China
| | - Hongke Huang
- Department of Cellular BiologyInstitute of BiomedicineNational Engineering Research Center of Genetic Medicine, Key Laboratory of Bioengineering Medicine of Guangdong Province, Jinan UniversityGuangzhou China
| | - Shiyin Lu
- Department of Cellular BiologyInstitute of BiomedicineNational Engineering Research Center of Genetic Medicine, Key Laboratory of Bioengineering Medicine of Guangdong Province, Jinan UniversityGuangzhou China
| | - Biqian Ou
- Department of Cellular BiologyInstitute of BiomedicineNational Engineering Research Center of Genetic Medicine, Key Laboratory of Bioengineering Medicine of Guangdong Province, Jinan UniversityGuangzhou China
| | - Jia Feng
- Department of Cellular BiologyInstitute of BiomedicineNational Engineering Research Center of Genetic Medicine, Key Laboratory of Bioengineering Medicine of Guangdong Province, Jinan UniversityGuangzhou China
| | - Wailan Shan
- Department of Cellular BiologyInstitute of BiomedicineNational Engineering Research Center of Genetic Medicine, Key Laboratory of Bioengineering Medicine of Guangdong Province, Jinan UniversityGuangzhou China
| | - Huixian Li
- Department of Cellular BiologyInstitute of BiomedicineNational Engineering Research Center of Genetic Medicine, Key Laboratory of Bioengineering Medicine of Guangdong Province, Jinan UniversityGuangzhou China
| | - Zixian Wang
- Department of Cellular BiologyInstitute of BiomedicineNational Engineering Research Center of Genetic Medicine, Key Laboratory of Bioengineering Medicine of Guangdong Province, Jinan UniversityGuangzhou China
| | - An Hong
- Department of Cellular BiologyInstitute of BiomedicineNational Engineering Research Center of Genetic Medicine, Key Laboratory of Bioengineering Medicine of Guangdong Province, Jinan UniversityGuangzhou China
| | - Yi Ma
- Department of Cellular BiologyInstitute of BiomedicineNational Engineering Research Center of Genetic Medicine, Key Laboratory of Bioengineering Medicine of Guangdong Province, Jinan UniversityGuangzhou China
| |
Collapse
|
11
|
Antunes MM, Godoy G, de Almeida-Souza CB, da Rocha BA, da Silva-Santi LG, Masi LN, Carbonera F, Visentainer JV, Curi R, Bazotte RB. A high-carbohydrate diet induces greater inflammation than a high-fat diet in mouse skeletal muscle. ACTA ACUST UNITED AC 2020; 53:e9039. [PMID: 32077465 PMCID: PMC7025447 DOI: 10.1590/1414-431x20199039] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Accepted: 12/16/2019] [Indexed: 01/09/2023]
Abstract
We previously reported that both the high-carbohydrate diet (HCD) and high-fat diet (HFD) given for two months promote lipid deposition and inflammation in the liver and brain of mice. The results obtained indicate a tissue-specific response to both diets. Herein, we compared the effects of HCD and HFD on fatty acid (FA) composition and inflammation in the gastrocnemius muscle. Male Swiss mice were fed with HCD or HFD for 1 or 2 months. Saturated FA (SFA), monounsaturated FA (MUFA), n-3 polyunsaturated FA (n-3 PUFA), and n-6 PUFA were quantified. The activities of stearoyl-CoA desaturase 1 (SCD-1), Δ-6 desaturase (D6D), elongase 6, and de novo lipogenesis (DNL) were estimated. As for indicators of the inflammatory tissue state, we measured myeloperoxidase (MPO) activity and gene expression of F4/80, tumor necrosis factor-α (TNF-α), interleukin (IL)-4, IL-6, and IL-10. The HCD led to a lower deposition of SFA, MUFA, n-3 PUFA, and n-6 PUFA compared to HFD. However, the HCD increased arachidonic acid levels, SFA/n-3 PUFA ratio, DNL, SCD-1, D6D, and MPO activities, and expression of IL-6, contrasting with the general idea that increased lipid deposition is associated with more intense inflammation. The HCD was more potent to induce skeletal muscle inflammation than the HFD, regardless of the lower lipid accumulation.
Collapse
Affiliation(s)
- M M Antunes
- Departamento de Farmacologia e Terapêutica, Universidade Estadual de Maringá, Maringá, PR, Brasil
| | - G Godoy
- Departamento de Farmacologia e Terapêutica, Universidade Estadual de Maringá, Maringá, PR, Brasil
| | - C B de Almeida-Souza
- Departamento de Farmacologia e Terapêutica, Universidade Estadual de Maringá, Maringá, PR, Brasil
| | - B A da Rocha
- Departamento de Farmacologia e Terapêutica, Universidade Estadual de Maringá, Maringá, PR, Brasil
| | - L G da Silva-Santi
- Departamento de Farmacologia e Terapêutica, Universidade Estadual de Maringá, Maringá, PR, Brasil
| | - L N Masi
- Programa de Pós-Graduação Interdisciplinar em Ciências da Saúde, Universidade Cruzeiro do Sul, São Paulo, SP, Brasil
| | - F Carbonera
- Departmento de Química, Universidade Estadual de Maringá, Maringá, PR, Brasil
| | - J V Visentainer
- Departmento de Química, Universidade Estadual de Maringá, Maringá, PR, Brasil
| | - R Curi
- Programa de Pós-Graduação Interdisciplinar em Ciências da Saúde, Universidade Cruzeiro do Sul, São Paulo, SP, Brasil
| | - R B Bazotte
- Departamento de Farmacologia e Terapêutica, Universidade Estadual de Maringá, Maringá, PR, Brasil
| |
Collapse
|
12
|
Chen Z, Wen D, Wang F, Wang C, Yang L. Curcumin protects against palmitic acid-induced apoptosis via the inhibition of endoplasmic reticulum stress in testicular Leydig cells. Reprod Biol Endocrinol 2019; 17:71. [PMID: 31472681 PMCID: PMC6717632 DOI: 10.1186/s12958-019-0517-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Accepted: 08/26/2019] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Palmitic acid (PA) is a common saturated fatty acid that induces apoptosis in various types of cells, including testicular Leydig cells. There is evidence suggesting that PA is increased in patients with obesity and that PA-induced cell apoptosis may play an important role in obesity-related male infertility. Curcumin, a natural polyphenol, has been reported to exert cytoprotective effects in various cell types. However, the cytoprotective effect of curcumin against PA-induced apoptosis in Leydig cells remains unknown. Therefore, the current study was performed to investigate the protective effects of curcumin in response to PA-induced toxicity and apoptosis in murine Leydig tumor cell line 1 (MLTC-1) cells and explore the mechanism underlying its anti-apoptotic action. METHODS MLTC-1 cells were cultured in Roswell Park Institute-1640 medium and divided into five groups. First four groups were treated with 50-400 μM PA, 400 μM PA + 5-40 μM curcumin, 400 μM PA + 500 nM 4-phenylbutyric acid (4-PBA, an endoplasmic reticulum (ER) stress inhibitor), and 500 nM thapsigargin (TG, an ER stress inducer) + 20 μM curcumin, respectively, followed by incubation for 24 h. Effects of PA and/or curcumin on viability, apoptosis, and ER stress in MLTC-1 cells were then determined by cell proliferation assay, flow cytometry, and western blot analysis. The fifth group of MLTC-1 cells was exposed to 400 μM of PA and 5 IU/mL of human chorionic gonadotropin (hCG) for 24 h in the absence and presence of curcumin, followed by measurement of testosterone levels in cell-culture supernatants by enzyme-linked immunosorbent assay (ELISA). Rats fed a high-fat diet (HFD) were treated with or without curcumin for 4 weeks, and the testosterone levels were detected by ELISA. RESULTS Exposure to 100-400 μM PA reduced cell viability, activated caspase 3, and enhanced the expression levels of the apoptosis-related protein BCL-2-associated X protein (BAX) and ER stress markers glucose-regulated protein 78 (GRP78) and CCAAT/enhancer binding protein homologous protein (CHOP) in MLTC-1 cells. Treating cells with 500 nM 4-PBA significantly attenuated PA-induced cytotoxicity through inhibition of ER stress. Curcumin (20 μM) significantly suppressed PA- or TG-induced decrease in cell viability, caspase 3 activity, and the expression levels of BAX, CHOP, and GRP78. In addition, treating MLTC-1 cells with 20 μM curcumin effectively restored testosterone levels, which were reduced in response to PA exposure. Similarly, curcumin treatment ameliorated the HFD-induced decrease in serum testosterone level in vivo. CONCLUSIONS The present study suggests that PA induces apoptosis via ER stress and curcumin ameliorates PA-induced apoptosis by inhibiting ER stress in MLTC-1 cells. This study suggests the application of curcumin as a potential therapeutic agent for the treatment of obesity-related male infertility.
Collapse
Affiliation(s)
- Zhi Chen
- College of Biological Science and Agriculture, Qiannan Normal University for Nationalities, Duyun, 558000, Guizhou, China
| | - Di Wen
- College of Biological Science and Agriculture, Qiannan Normal University for Nationalities, Duyun, 558000, Guizhou, China
| | - Fen Wang
- College of Biological Science and Agriculture, Qiannan Normal University for Nationalities, Duyun, 558000, Guizhou, China
| | - Chunbo Wang
- College of Biological Science and Agriculture, Qiannan Normal University for Nationalities, Duyun, 558000, Guizhou, China
| | - Lei Yang
- Key Laboratory of System Bio-medicine of Jiangxi Province, Jiujiang University, Jiujiang, 332000, Jiangxi, China.
- College of Basic Medical Science, Jiujiang University, Jiujiang, 332000, Jiangxi, China.
| |
Collapse
|
13
|
Savage DB, Watson L, Carr K, Adams C, Brage S, Chatterjee KK, Hodson L, Boesch C, Kemp GJ, Sleigh A. Accumulation of saturated intramyocellular lipid is associated with insulin resistance. J Lipid Res 2019; 60:1323-1332. [PMID: 31048405 PMCID: PMC6602127 DOI: 10.1194/jlr.m091942] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 03/11/2019] [Indexed: 12/17/2022] Open
Abstract
Intramyocellular lipid (IMCL) accumulation has been linked to both insulin-resistant and insulin-sensitive (athletes) states. Biochemical analysis of intramuscular triglyceride composition is confounded by extramyocellular triglycerides in biopsy samples, and hence the specific composition of IMCLs is unknown in these states. 1H magnetic resonance spectroscopy (MRS) can be used to overcome this problem. Thus, we used a recently validated 1H MRS method to compare the compositional saturation index (CH2:CH3) and concentration independent of the composition (CH3) of IMCLs in the soleus and tibialis anterior muscles of 16 female insulin-resistant lipodystrophic subjects with that of age- and gender-matched athletes (n = 14) and healthy controls (n = 41). The IMCL CH2:CH3 ratio was significantly higher in both muscles of the lipodystrophic subjects compared with controls but was similar in athletes and controls. IMCL CH2:CH3 was dependent on the IMCL concentration in the controls and, after adjusting the compositional index for quantity (CH2:CH3adj), could distinguish lipodystrophics from athletes. This CH2:CH3adj marker had a stronger relationship with insulin resistance than IMCL concentration alone and was inversely related to VO2max The association of insulin resistance with the accumulation of saturated IMCLs is consistent with a potential pathogenic role for saturated fat and the reported benefits of exercise and diet in insulin-resistant states.
Collapse
Affiliation(s)
- David B Savage
- Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science, Cambridge Biomedical Campus, Cambridge, United Kingdom
| | - Laura Watson
- National Institute for Health Research/Wellcome Trust Clinical Research Facility, Cambridge University Hospitals NHS Foundation Trust Cambridge Biomedical Campus, Cambridge, United Kingdom
| | - Katie Carr
- National Institute for Health Research/Wellcome Trust Clinical Research Facility, Cambridge University Hospitals NHS Foundation Trust Cambridge Biomedical Campus, Cambridge, United Kingdom
| | - Claire Adams
- Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science, Cambridge Biomedical Campus, Cambridge, United Kingdom
| | - Soren Brage
- MRC Epidemiology Unit University of Cambridge School of Clinical Medicine, Cambridge, United Kingdom
| | - Krishna K Chatterjee
- Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science, Cambridge Biomedical Campus, Cambridge, United Kingdom
- National Institute for Health Research/Wellcome Trust Clinical Research Facility, Cambridge University Hospitals NHS Foundation Trust Cambridge Biomedical Campus, Cambridge, United Kingdom
| | - Leanne Hodson
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Chris Boesch
- Department of Clinical Research and Radiology AMSM, University Bern, Bern, Switzerland
| | - Graham J Kemp
- Department of Musculoskeletal Biology University of Liverpool and MRC-Arthritis Research UK Centre for Integrated Research into Musculoskeletal Ageing, Liverpool, United Kingdom
| | - Alison Sleigh
- Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science, Cambridge Biomedical Campus, Cambridge, United Kingdom
- National Institute for Health Research/Wellcome Trust Clinical Research Facility, Cambridge University Hospitals NHS Foundation Trust Cambridge Biomedical Campus, Cambridge, United Kingdom
- Wolfson Brain Imaging Centre University of Cambridge School of Clinical Medicine, Cambridge, United Kingdom
| |
Collapse
|
14
|
Liu Q, Li R, Chen G, Wang J, Hu B, Li C, Zhu X, Lu Y. Inhibitory effect of 17β‑estradiol on triglyceride synthesis in skeletal muscle cells is dependent on ESR1 and not ESR2. Mol Med Rep 2019; 19:5087-5096. [PMID: 31059046 PMCID: PMC6522926 DOI: 10.3892/mmr.2019.10189] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Accepted: 03/13/2019] [Indexed: 12/02/2022] Open
Abstract
The present study aimed to investigate the inhibitory effects and the mechanisms underlying 17β-estradiol (E2) effects on triglyceride synthesis and insulin resistance in skeletal muscle tissues and cells. Ovariectomy (OVX) was performed on 6-month-old female rats treated with or without E2. Subsequently, various serum biochemical markers were measured. Additionally, pathological alterations of the uterus, liver and skeletal muscle were analyzed, and the content of triglycerides (TG) in muscle was detected. Differentiated myotubes formed by C2C12 cells were treated with palmitic acid (PA) or pretreated with E2, estrogen receptor (ESR) 1 agonist propylpyrazoletriol (PPT) and ESR2 agonist diarylpropionitrile (DPN). Subsequently, the mRNA or protein expression levels of ESR1/2, peroxisome proliferator activated receptor α (PPARα), CD36 molecule (CD36), fatty acid synthase (FASN), perilipin 2 (PLIN2), phosphorylated acetyl-CoA carboxylase α (p-ACACA), p-AKT serine/threonine kinase (p-AKT) and p-mitogen-activated protein kinase 8 (p-MAPK8) were analyzed in skeletal muscle or in C2C12 cells by reverse transcription-semi-quantitative polymerase chain reaction and western blotting. The present results suggested that treatment with E2 inhibited OVX-induced body weight gain, TG accumulation and insulin resistance. The protein or mRNA expression levels of ESR1, CD36, PPARα, p-ACACA and p-AKT were decreased, whereas the protein or mRNA expression levels of ESR2, PLIN2, FASN and p-MAPK8 were increased in the OVX group. Of note, treatment with E2 restored the expression levels of the aforementioned factors. In C2C12 cells, treatment with E2 or PPT reversed the alterations induced by treatment with PA. In contrast, pretreatment with DPN did not influence the effect of PA. Collectively, E2 was able to interact with ESR1, thus activating the CD36-PPARα pathway, decreasing the level of TG in the muscles and improving insulin resistance in skeletal muscles and C2C12 cells.
Collapse
Affiliation(s)
- Quan Liu
- Department of Clinical Pharmacy, Class 2014, School of Pharmacy, Anhui Medical University, Hefei, Anhui 230032, P.R. China
| | - Rui Li
- Department of Clinical Pharmacy, Class 2014, School of Pharmacy, Anhui Medical University, Hefei, Anhui 230032, P.R. China
| | - Guanjun Chen
- Center of Scientific Research, Anhui Medical University, Hefei, Anhui 230032, P.R. China
| | - Jianming Wang
- Dalian Maple International School, Dalian, Liaoning 116100, P.R. China
| | - Bingfeng Hu
- Department of Clinical Pharmacy, Class 2014, School of Pharmacy, Anhui Medical University, Hefei, Anhui 230032, P.R. China
| | - Chaofei Li
- The Comprehensive Laboratory, Anhui Medical University, Hefei, Anhui 230032, P.R. China
| | - Xiaohuan Zhu
- Department of Endocrinology, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui 230032, P.R. China
| | - Yunxia Lu
- The Comprehensive Laboratory, Anhui Medical University, Hefei, Anhui 230032, P.R. China
| |
Collapse
|
15
|
Three days of a eucaloric, low-carbohydrate/high-fat diet increases insulin clearance in healthy non-obese Japanese men. Sci Rep 2019; 9:3857. [PMID: 30846785 PMCID: PMC6405898 DOI: 10.1038/s41598-019-40498-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Accepted: 02/18/2019] [Indexed: 12/17/2022] Open
Abstract
Metabolic clearance rate of insulin (MCRI) is thought to help maintain glucose homeostasis even in healthy subjects. However, the effect of a low carbohydrate/high fat (LCHF) diet on MCRI in healthy subject remains unclear. To investigate the effect of a 3-day eucaloric LCHF diet on MCRI in healthy subjects, we studied 42 healthy non-obese Japanese men. Each subject consumed a eucaloric LCHF diet for 3 days. Before and after the LCHF diet, intramyocellular lipid (IMCL) levels were measured using 1H-magnetic resonance spectroscopy, and glucose infusion rate (GIR) and MCRI were evaluated with a euglycemic hyperinsulinemic clamp. The LCHF diet increased MCRI by 10% and decreased steady state serum insulin (SSSI) and GIR during glucose clamp by 10% and 6%, respectively. To further investigate the role of MCRI, we divided subjects into high-responder (HR) and low-responder (LR) groups based on the median %change in MCRI. The LCHF diet increased IMCL and decreased SSSI during glucose clamp in the HR group, while those were not altered in the LR group. Our results suggested that a 3-day eucaloric LCHF diet increases MCRI in healthy non-obese Japanese men. This change seemed to be beneficial in terms of maintaining euglycemia during low carbohydrate availability.
Collapse
|
16
|
Metcalfe LK, Smith GC, Turner N. Defining lipid mediators of insulin resistance - controversies and challenges. J Mol Endocrinol 2018; 62:JME-18-0023. [PMID: 30068522 DOI: 10.1530/jme-18-0023] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 07/04/2018] [Accepted: 07/31/2018] [Indexed: 12/31/2022]
Abstract
Essential elements of all cells, lipids play important roles in energy production, signalling and as structural components. Despite these critical functions, excessive availability and intracellular accumulation of lipid is now recognised as a major factor contributing to many human diseases, including obesity and diabetes. In the context of these metabolic disorders, ectopic deposition of lipid has been proposed to have deleterious effects of insulin action. While this relationship has been recognised for some time now, there is currently no unifying mechanism to explain how lipids precipitate the development of insulin resistance. This review summarises the evidence linking specific lipid molecules to the induction of insulin resistance, describing some of the current controversies and challenges for future studies in this field.
Collapse
Affiliation(s)
- Louise K Metcalfe
- L Metcalfe, Department of Pharmacology, School of Medical Sciences, UNSW Australia, Kensington, Australia
| | - Greg C Smith
- G Smith, Department of Pharmacology, School of Medical Sciences, UNSW Australia, Kensington, Australia
| | - Nigel Turner
- N Turner, Department of Pharmacology, School of Medical Sciences, University of New South Wales, Sydney, Australia
| |
Collapse
|
17
|
Royal jelly supplementation reduces skeletal muscle lipotoxicity and insulin resistance in aged obese rats. ACTA ACUST UNITED AC 2018; 25:307-315. [PMID: 29960833 DOI: 10.1016/j.pathophys.2018.05.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 04/28/2018] [Accepted: 05/03/2018] [Indexed: 02/08/2023]
Abstract
BACKGROUND Consumption of a high-fat diet (HFD) in aged rats is associated with several metabolic disorders. The mechanism of skeletal muscle lipotoxicity and insulin resistance (IR) is multi-factorial, but the exact mechanism of how aging affects these processes unknown. Royal jelly (RJ) is a dietary supplement with many physiological and pharmacological properties. No previous studies have demonstrated the protective effects and mechanism of RJ in aged obese rats. OBJECTIVES The study was carried to investigate the effects of aging and HFD on skeletal muscles, and adipose tissue metabolism and inflammation, in aged rats, and whether RJ could combat such adverse effects. METHODOLOGY A total of 40 male rats were divided into5 groups; young rats fed a standard diet, aged rats fed a standard diet, aged rats fed RJ, aged rats fed a HFD, and aged rats fed both a HFD and RJ for 8 weeks. We investigated changes in body weights (BW), abdominal fat weights, total cholesterol, triglycerides (TG), low density lipoprotein-cholesterol (LDL-c), high density lipoprotein-cholesterol (HDL-c), muscle TG, and IR levels. Also, concentrations of TNF-α receptor 1(TNFR1) were estimated in the serum and adipose tissues. RESULTS Aged, obese rats showed increased BW, adipose weights, IR, and disturbed serum and muscle lipids. Also, TNFR1 was increased. Rats fed RJ showed decreased adiposity, improved lipids' profiles, improved IR, and decreased TNFR1. CONCLUSION Aging and HFD were associated with disturbed metabolism, and muscle lipotoxicity and inflammation, while RJ could counteract muscle lipotoxicity in rats and reduce IR, most likely due to an anti-inflammatory effect.
Collapse
|
18
|
Yang WS, Chen PC, Hsu HC, Su TC, Lin HJ, Chen MF, Lee YT, Chien KL. Differential effects of saturated fatty acids on the risk of metabolic syndrome: a matched case-control and meta-analysis study. Metabolism 2018; 83:42-49. [PMID: 29410352 DOI: 10.1016/j.metabol.2018.01.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2017] [Revised: 01/09/2018] [Accepted: 01/17/2018] [Indexed: 01/21/2023]
Abstract
BACKGROUND We investigated the association between plasma saturated fatty acids (SFAs) and the risk of metabolic syndrome among ethnic Chinese adults in Taiwan who attended a health check-up center. METHODS A case-control study based on 1000 cases of metabolic syndrome and 1:1 matched control participants (mean age, 54.9 ± 10.7 y; 36% females) were recruited. Metabolic syndrome was defined according to the criteria of the International Diabetes Federation. Gas chromatography was used to measure the distribution of fatty acids in plasma (% of total fatty acids). RESULTS Even-chain SFAs, including 14:0, 16:0, and 18:0, were associated with metabolic syndrome; the adjusted odds ratio [OR] and 95% confidence interval [CI] per standard deviation [SD] difference was 3.32, [1.98-5.59]; however, very-long-chain SFAs, including 20:0, 21:0, 22:0, 23:0, and 24:0, were inversely associated with metabolic syndrome. The adjusted OR [95% CI] per SD difference was 0.67 [0.58-0.78]. The area under the receiver operative characteristic curve increased from 0.814 in the basic model to 0.815 (p = 0.54, compared with the basic model), 0.818 (p < 0.0001), and 0.820 (p < 0.0001) after adding odd-chain, even-chain, and very-long chain SFAs. A meta-analysis based on 12 studies showed that the summarized OR for type 2 diabetes mellitus was 1.16 [0.96-1.41] for the top versus bottom SFAs. CONCLUSIONS Different carbon numbers of SFAs have been shown to have differential effects on the status of metabolic syndrome, implying that SFAs are not homogenous for the effects.
Collapse
Affiliation(s)
- Wei-Sin Yang
- Institute of Epidemiology & Preventive Medicine, College of Public School, National Taiwan University, Taipei 100, Taiwan
| | - Pei-Chun Chen
- Department of Public Health, China Medical University, Taichung 404, Taiwan
| | - Hsiu-Ching Hsu
- Department of Internal Medicine, National Taiwan University Hospital, Taipei 100, Taiwan
| | - Ta-Chen Su
- Department of Internal Medicine, National Taiwan University Hospital, Taipei 100, Taiwan
| | - Hung-Ju Lin
- Department of Internal Medicine, National Taiwan University Hospital, Taipei 100, Taiwan
| | - Ming-Fong Chen
- Department of Internal Medicine, National Taiwan University Hospital, Taipei 100, Taiwan; Cardiovascular Research Laboratory, Cardiovascular Center, Clinical Outcome Research and Training Center, Big Data Center, China Medical University, Hospital, China Medical University, Taichung 404, Taiwan
| | - Yuan-Teh Lee
- Department of Internal Medicine, National Taiwan University Hospital, Taipei 100, Taiwan
| | - Kuo-Liong Chien
- Institute of Epidemiology & Preventive Medicine, College of Public School, National Taiwan University, Taipei 100, Taiwan; Department of Internal Medicine, National Taiwan University Hospital, Taipei 100, Taiwan.
| |
Collapse
|
19
|
Kim JE, Dunville K, Li J, Cheng JX, Conley TB, Couture CS, Campbell WW. Intermuscular Adipose Tissue Content and Intramyocellular Lipid Fatty Acid Saturation Are Associated with Glucose Homeostasis in Middle-Aged and Older Adults. Endocrinol Metab (Seoul) 2017; 32:257-264. [PMID: 28555462 PMCID: PMC5503871 DOI: 10.3803/enm.2017.32.2.257] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Revised: 03/21/2017] [Accepted: 03/30/2017] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Insulin resistance is associated with the higher content of intermuscular adipose tissue (IMAT) and the saturation of intramyocellular lipid (IMCL), but a paucity of data exist in humans. This study examined associations among IMAT content, IMCL saturation, and fasting glucose concentration in middle-aged and older adults with overweight or obesity. METHODS Seventy-five subjects (26 males, 49 females) were recruited and thigh muscle and IMAT were assessed using magnetic resonance imaging. Vastus lateralis tissue was acquired from a subset of nine subjects and IMCL content and saturation were assessed using nonlinear dual complex microscopy. RESULTS The characteristics of the 75 subjects were as follows: age 59±11 years, body mass index 30±5 kg/m², fasting glucose concentration 5.2±0.5 mmol/L, fasting insulin concentration 12.2±7.3 μU/mL, fasting homeostatic model assessment of insulin resistance (HOMA-IR) 2.9±2.0 (mean±SD). IMAT to muscle tissue (MT) volume ratio was positively associated with the saturated fatty acid to unsaturated fatty acid ratio in IMCL. IMAT:MT was positively associated with fasting glucose concentration and HOMA-IR. IMCL saturation was positively associated with fasting glucose concentration while muscle cell area, IMCL area, and % IMCL in muscle cell were not associated with fasting glucose concentration. CONCLUSION These results indicate that higher intermuscular fat content and IMCL saturation may impact fasting glucose concentration in middle-aged and older adults with overweight or obesity. The centralization of adipose tissue in the appendicular region of the body may promote insulin resistance.
Collapse
Affiliation(s)
- Jung Eun Kim
- Department of Nutrition Science, Purdue University College of Health and Human Sciences, West Lafayette, IN, USA
| | - Keagan Dunville
- Department of Chemistry, Purdue University College of Science, West Lafayette, IN, USA
| | - Junjie Li
- Weldon School of Biomedical Engineering, Purdue University College of Engineering, West Lafayette, IN, USA
| | - Ji Xin Cheng
- Weldon School of Biomedical Engineering, Purdue University College of Engineering, West Lafayette, IN, USA
| | - Travis B Conley
- Department of Nutrition Science, Purdue University College of Health and Human Sciences, West Lafayette, IN, USA
| | - Cortni S Couture
- Department of Chemistry, Purdue University College of Science, West Lafayette, IN, USA
| | - Wayne W Campbell
- Department of Nutrition Science, Purdue University College of Health and Human Sciences, West Lafayette, IN, USA.
| |
Collapse
|
20
|
Lindeboom L, de Graaf RA. Measurement of lipid composition in human skeletal muscle and adipose tissue with1H-MRS homonuclear spectral editing. Magn Reson Med 2017; 79:619-627. [DOI: 10.1002/mrm.26740] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Revised: 03/15/2017] [Accepted: 04/10/2017] [Indexed: 01/13/2023]
Affiliation(s)
- Lucas Lindeboom
- Department of Radiology; NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center; Maastricht the Netherlands
- Department of Human Biology/Human Movement Sciences; NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center; Maastricht the Netherlands
| | - Robin A. de Graaf
- Department of Radiology and Biomedical Imaging; Magnetic Resonance Research Center, Yale University School of Medicine; New Haven Connecticut USA
| |
Collapse
|
21
|
Diet-induced obesity impairs spermatogenesis: a potential role for autophagy. Sci Rep 2017; 7:43475. [PMID: 28276438 PMCID: PMC5343591 DOI: 10.1038/srep43475] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Accepted: 01/25/2017] [Indexed: 12/11/2022] Open
Abstract
Autophagy is an evolutionarily conserved process that plays a crucial role in maintaining a series of cellular functions. It has been found that autophagy is closely involved in the physiological process of spermatogenesis and the regulation of sperm survival and motility. However, the role of autophagy in high-fat diet (HFD)-induced impaired spermatogenesis remains unknown. This study was designed to investigate the role of autophagy in HFD-induced spermatogenesis deficiency and employed chloroquine (CQ) to inhibit autophagy and rapamycin (RAP) to induce autophagy. 3-methyladenine (3-MA) and CQ were administered via intratesticular injection in vivo. The effects of CQ and 3-MA on the parameters of spermatozoa co-cultured with palmitic acid (PA) in vitro were also investigated. Human semen samples from obese, subfertile male patients were also collected to examine the level of autophagy. The results suggested that HFD mice subjected to CQ showed improved spermatogenesis. Inhibiting autophagy with CQ improved the decreased fertility of HFD male mice. Moreover, the in vivo and in vitro results indicated that both CQ and 3-MA could suppress the pathological changes in spermatozoa caused by HFD or PA treatment. Additionally, the excessive activation of autophagy was also observed in sperm samples from obese, subfertile male patients.
Collapse
|
22
|
Fukuchi S, Hamaguchi K, Seike M, Himeno K, Sakata T, Yoshimatsu H. Role of Fatty Acid Composition in the Development of Metabolic Disorders in Sucrose-Induced Obese Rats. Exp Biol Med (Maywood) 2016; 229:486-93. [PMID: 15169967 DOI: 10.1177/153537020422900606] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Fatty acids have been shown to be involved in the development of insulin resistance associated with obesity. We used sucrose loading in rats to analyze changes in fatty acid composition in the progression of obesity and the related metabolic disorder. Although rats fed a sucrose diet for 4 weeks had body weights similar to those of control animals, their visceral fat pads were significantly larger, and serum triglyceride levels were higher; however, neither plasma glucose nor insulin levels were significantly higher. After 20 weeks of sucrose loading, body weight and visceral and subcutaneous fat pads had increased significantly compared with those in control rats. Moreover, plasma glucose, Insulin, and triglyceride levels were significantly higher. An analysis of individual fatty acid components in the blood and peripheral tissues demonstrated phase- and tissue-dependent changes. After 20 weeks of sucrose loading, palmitoleic acid (16:1 n-7) and oleic acid (18:1 n-9), the major components of monounsaturated fatty acid, showed a ubiquitous increase in plasma and all tissues analyzed. In contrast, linoleic acid (18:2 n-6) and arachidonic acid (20:4 n-6), the major components of polyunsaturated fatty acid in the n-6 family, decreased in plasma and all tissues analyzed. After 4 weeks of sucrose loading, these changes in fatty acid composition were observed only in the liver and plasma and not in fat and muscle. This led us to conclude that elevation of plasma glucose and insulin develop at the late phase of sucrose-induced obesity, when changes in fatty acid composition appear in fat and muscle. Furthermore, changes in fatty acid composition in liver seen after 4 weeks of sucrose loading, when increases in neither plasma glucose nor insulin were detected, suggest that liver may be the initial site of fatty acid imbalance and that aberrations in hepatic fatty acid composition may lead to fatty acid imbalances in other tissues.
Collapse
Affiliation(s)
- Satoshi Fukuchi
- Department of Internal Medicine I, Faculty of Medicine, Oita University, Hasama, Oita, 879-5593, Japan
| | | | | | | | | | | |
Collapse
|
23
|
Ashworth WB, Davies NA, Bogle IDL. A Computational Model of Hepatic Energy Metabolism: Understanding Zonated Damage and Steatosis in NAFLD. PLoS Comput Biol 2016; 12:e1005105. [PMID: 27632189 PMCID: PMC5025084 DOI: 10.1371/journal.pcbi.1005105] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Accepted: 08/12/2016] [Indexed: 12/20/2022] Open
Abstract
In non-alcoholic fatty liver disease (NAFLD), lipid build-up and the resulting damage is known to occur more severely in pericentral cells. Due to the complexity of studying individual regions of the sinusoid, the causes of this zone specificity and its implications on treatment are largely ignored. In this study, a computational model of liver glucose and lipid metabolism is presented which treats the sinusoid as the repeating unit of the liver rather than the single hepatocyte. This allows for inclusion of zonated enzyme expression by splitting the sinusoid into periportal to pericentral compartments. By simulating insulin resistance (IR) and high intake diets leading to the development of steatosis in the model, we identify key differences between periportal and pericentral cells accounting for higher susceptibility to pericentral steatosis. Secondly, variation between individuals is seen in both susceptibility to steatosis and in its development across the sinusoid. Around 25% of obese individuals do not show excess liver fat, whilst 16% of lean individuals develop NAFLD. Furthermore, whilst pericentral cells tend to show higher lipid levels, variation is seen in the predominant location of steatosis from pericentral to pan-sinusoidal or azonal. Sensitivity analysis was used to identify the processes which have the largest effect on both total hepatic triglyceride levels and on the sinusoidal location of steatosis. As is seen in vivo, steatosis occurs when simulating IR in the model, predominantly due to increased uptake, along with an increase in de novo lipogenesis. Additionally, concentrations of glucose intermediates including glycerol-3-phosphate increased when simulating IR due to inhibited glycogen synthesis. Several differences between zones contributed to a higher susceptibility to steatosis in pericentral cells in the model simulations. Firstly, the periportal zonation of both glycogen synthase and the oxidative phosphorylation enzymes meant that the build-up of glucose intermediates was less severe in the periportal hepatocyte compartments. Secondly, the periportal zonation of the enzymes mediating β-oxidation and oxidative phosphorylation resulted in excess fats being metabolised more rapidly in the periportal hepatocyte compartments. Finally, the pericentral expression of de novo lipogenesis contributed to pericentral steatosis when additionally simulating the increase in sterol-regulatory element binding protein 1c (SREBP-1c) seen in NAFLD patients in vivo. The hepatic triglyceride concentration was predicted to be most sensitive to inter-individual variation in the activity of enzymes which, either directly or indirectly, determine the rate of free fatty acid (FFA) oxidation. The concentration was most strongly dependent on the rate constants for β-oxidation and oxidative phosphorylation. It also showed moderate sensitivity to the rate constants for processes which alter the allosteric inhibition of β-oxidation by acetyl-CoA. The predominant sinusoidal location of steatosis meanwhile was most sensitive variations in the zonation of proteins mediating FFA uptake or triglyceride release as very low density lipoproteins (VLDL). Neither the total hepatic concentration nor the location of steatosis showed strong sensitivity to variations in the lipogenic rate constants.
Collapse
Affiliation(s)
- William B. Ashworth
- Institute of Liver and Digestive Health, University College London, London, United Kingdom
- Department of Chemical Engineering, University College London, London, United Kingdom
- CoMPLEX, University College London, London, United Kingdom
| | - Nathan A. Davies
- Institute of Liver and Digestive Health, University College London, London, United Kingdom
| | - I. David L. Bogle
- Department of Chemical Engineering, University College London, London, United Kingdom
- * E-mail:
| |
Collapse
|
24
|
Dotzert MS, Murray MR, McDonald MW, Olver TD, Velenosi TJ, Hennop A, Noble EG, Urquhart BL, Melling CWJ. Metabolomic Response of Skeletal Muscle to Aerobic Exercise Training in Insulin Resistant Type 1 Diabetic Rats. Sci Rep 2016; 6:26379. [PMID: 27197730 PMCID: PMC4873835 DOI: 10.1038/srep26379] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Accepted: 04/28/2016] [Indexed: 12/21/2022] Open
Abstract
The etiology of insulin resistance in Type 1 Diabetes (T1D) is unknown, however it affects approximately 20% of T1D patients. Intramyocellular lipids (IMCL) have been identified as a mechanism of insulin resistance. We examined skeletal muscle of T1D rats to determine if alterations in lipid metabolism were evident and whether aerobic exercise training improves IMCL and insulin resistance. To do so, 48 male Sprague-Dawley rats were divided into control (C), sedentary diabetes (D) and diabetes exercise (DX) groups. Following multiple low-dose Streptozotocin (STZ) injections (20 mg/kg), glycemia (9-15 mM) was maintained using insulin treatment. DX were treadmill trained at high intensity (~75% V02max; 5days/week) for 10 weeks. The results demonstrate that D exhibited insulin resistance compared with C and DX, indicated by decreased glucose infusion rate during a hyperinsulinemic-euglycemic clamp (p < 0.05). There were no differences between C and DX, suggesting that exercise improved insulin resistance (p < 0.05). Metabolomics analysis revealed a significant shift in lipid metabolism whereby notable fatty acid metabolites (arachidonic acid, palmitic acid and several polyunsaturated fatty acids) were significantly elevated in D compared to C and DX. Based on the intermediates observed, insulin resistance in T1D is characterized by an insulin-desensitizing intramyocellular fatty acid metabolite profile that is ameliorated with exercise training.
Collapse
Affiliation(s)
- Michelle S. Dotzert
- Exercise Biochemistry Laboratory, School of Kinesiology, Western University, London, Ontario, Canada
| | - Michael R. Murray
- Exercise Biochemistry Laboratory, School of Kinesiology, Western University, London, Ontario, Canada
| | - Matthew W. McDonald
- Exercise Biochemistry Laboratory, School of Kinesiology, Western University, London, Ontario, Canada
| | - T. Dylan Olver
- Neurovascular Research Laboratory, School of Kinesiology, Western University, London, Ontario, Canada
| | - Thomas J. Velenosi
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Anzel Hennop
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Earl G. Noble
- Exercise Biochemistry Laboratory, School of Kinesiology, Western University, London, Ontario, Canada
| | - Brad L. Urquhart
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
- Lawson Health Research Institute, London, Ontario, Canada
- Department of Medicine, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - C. W. James Melling
- Exercise Biochemistry Laboratory, School of Kinesiology, Western University, London, Ontario, Canada
| |
Collapse
|
25
|
Kratochvílová S, Škoch A, Wohl P, Švehlíková E, Dezortová M, Hill M, Hájek M, Pelikánová T. Intramyocellular lipid content in subjects with impaired fasting glucose after telmisartan treatment, a randomised cross-over trial. Magn Reson Imaging 2015; 34:353-8. [PMID: 26523653 DOI: 10.1016/j.mri.2015.10.031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Accepted: 10/21/2015] [Indexed: 10/22/2022]
Abstract
Ectopic lipid accumulation in skeletal muscle is associated with insulin resistance. Telmisartan improves metabolic parameters in type 2 diabetic patients. The aim of our study was to evaluate the in vivo effect of telmisartan on intramyocellular lipid content (IMCL) in subjects with impaired fasting glucose (IFG) by magnetic resonance spectroscopy (MRS). We enrolled 10 subjects with IFG in a cross-over, placebo-controlled, randomized, double-blind trial, treated with 3 weeks of telmisartan (160 mg daily) or placebo. After completing each treatment, a hyperinsulinaemic euglycaemic clamp (1 mU/kg per min; 5 mmol/l; 120 min) to assess insulin action (metabolic clearance rate of glucose, MCR) and (1)H MRS of the m. tibialis anterior using a MR Scanner Siemens Vision operating at 1.5 T to evaluate IMCL content, were performed. Plasma adipokine levels were determined simultaneously. Telmisartan treatment resulted in a lower fasting plasma glucose (FPG) (p < 0.05), but insulin action was comparable to after placebo. Telmisartan did not affect IMCL content. After placebo, IMCL correlated negatively with total cholesterol (p < 0.001), MCR (p < 0.05) and adiponectin (p < 0.05) and positively with FPG (p < 0.05). After telmisartan treatment there was only a positive correlation between IMCL and TNFα (p < 0.05). IMCL content is related to parameters of glucose metabolism and insulin action in sedentary IFG subjects. A short telmisartan treatment did not affect the IMCL content despite its positive effect on FPG. The improvement in FPG was probably mediated through interference with other metabolic pathways.
Collapse
Affiliation(s)
- Simona Kratochvílová
- Diabetes Center, Institute for Clinical and Experimental Medicine, Vídeňská 1958/4, Prague 140 21, Czech Republic
| | - Antonín Škoch
- MR Unit, Department of Diagnostic and Interventional Radiology, Institute for Clinical and Experimental Medicine, Vídeňská 1958/4, Prague 140 21, Czech Republic
| | - Petr Wohl
- Diabetes Center, Institute for Clinical and Experimental Medicine, Vídeňská 1958/4, Prague 140 21, Czech Republic
| | - Eva Švehlíková
- Diabetes Center, Institute for Clinical and Experimental Medicine, Vídeňská 1958/4, Prague 140 21, Czech Republic
| | - Monika Dezortová
- MR Unit, Department of Diagnostic and Interventional Radiology, Institute for Clinical and Experimental Medicine, Vídeňská 1958/4, Prague 140 21, Czech Republic
| | - Martin Hill
- Institute of Endocrinology, Národní 8, Prague 116 94, Czech Republic
| | - Milan Hájek
- MR Unit, Department of Diagnostic and Interventional Radiology, Institute for Clinical and Experimental Medicine, Vídeňská 1958/4, Prague 140 21, Czech Republic
| | - Terezie Pelikánová
- Diabetes Center, Institute for Clinical and Experimental Medicine, Vídeňská 1958/4, Prague 140 21, Czech Republic.
| |
Collapse
|
26
|
Rosiglitazone, but not epigallocatechin-3-gallate, attenuates the decrease in PGC-1α protein levels in palmitate-induced insulin-resistant C2C12 cells. Lipids 2015; 50:521-8. [PMID: 25893813 DOI: 10.1007/s11745-015-4016-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Accepted: 03/27/2015] [Indexed: 01/29/2023]
Abstract
Alteration of lipid metabolism is an important mechanism for the treatment of insulin resistance. PGC-1α, a key regulator of mitochondrial biogenesis and function, plays an important role in the improvement of insulin sensitivity by increasing fatty acids β-oxidation. In the present study, the effects of epigallocatechin-3-gallate (EGCG), an anti-obesity agent and enhancer of lipid catabolism, on PGC-1α protein expression was examined and compared with anti-diabetic drug rosiglitazone (RGZ). After differentiation of C2C12 myoblasts to myotubes, insulin resistance was induced by palmitate treatment. Then the expression of the PGC-1a gene and glucose uptake were evaluated before and after treatment with RGZ and EGCG. Palmitate treatment significantly decreased PGC-1α protein expression in C2C12 cells (P < 0.05). RGZ could restore the expression of PGC-1α in palmitate treated cells (P > 0.05), while EGCG had no significant effect on the expression of this gene (P < 0.05). RGZ and EGCG significantly improved glucose uptake (by 2- and 1.54-fold, respectively) in myotubes treated with palmitate. These data suggest that RGZ and EGCG both exert their anti-diabetic activity by increasing insulin sensitivity, but with different molecular mechanisms. This effect of RGZ, unlike EGCG, is mediated, at least partly, by increasing PGC-1α protein expression.
Collapse
|
27
|
Ruschke S, Kienberger H, Baum T, Kooijman H, Settles M, Haase A, Rychlik M, Rummeny EJ, Karampinos DC. Diffusion-weighted stimulated echo acquisition mode (DW-STEAM) MR spectroscopy to measure fat unsaturation in regions with low proton-density fat fraction. Magn Reson Med 2015; 75:32-41. [DOI: 10.1002/mrm.25578] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Revised: 10/29/2014] [Accepted: 11/20/2014] [Indexed: 12/23/2022]
Affiliation(s)
- Stefan Ruschke
- Department of Diagnostic and Interventional Radiology; Technische Universität München; Munich Germany
| | - Hermine Kienberger
- Bioanalytik Weihenstephan; Research Center for Nutrition and Food Sciences, Technische Universität München; Freising Germany
| | - Thomas Baum
- Department of Diagnostic and Interventional Radiology; Technische Universität München; Munich Germany
| | | | - Marcus Settles
- Department of Diagnostic and Interventional Radiology; Technische Universität München; Munich Germany
| | - Axel Haase
- Zentralinstitut für; Medizintechnik; Technische Universität München; Garching Germany
| | - Michael Rychlik
- Bioanalytik Weihenstephan; Research Center for Nutrition and Food Sciences, Technische Universität München; Freising Germany
- Chair of Analytical Food Chemistry; Technische Universität München; Freising Germany
| | - Ernst J. Rummeny
- Department of Diagnostic and Interventional Radiology; Technische Universität München; Munich Germany
| | - Dimitrios C. Karampinos
- Department of Diagnostic and Interventional Radiology; Technische Universität München; Munich Germany
| |
Collapse
|
28
|
Wei Z, Lin L, Wang C, Yang J, Liu G, Zhong J, Lin Y, Chen Z. High-resolution localized spatiotemporal encoding correlated spectra under inhomogeneous magnetic fields via asymmetrical gradient encoding/decoding. NMR IN BIOMEDICINE 2015; 28:210-216. [PMID: 25504877 DOI: 10.1002/nbm.3241] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Revised: 11/03/2014] [Accepted: 11/06/2014] [Indexed: 06/04/2023]
Abstract
Applications of conventional localized nuclear magnetic resonance correlated spectroscopy are restrained by long acquisition times and poor performance under inhomogeneous magnetic fields. Here, a method that combines the spatiotemporal encoding technique with the localization technique and implements the encoding and decoding in unison with suitable asymmetrical gradients is proposed to obtain high-resolution localized correlated spectra under inhomogeneous fields in greatly reduced times. Experiments on phantom solutions prove its insensitivity to linear field inhomogeneities along three orthogonal axes. Moreover, this method is applied to adipose study of marrow tissue with resolution improvements. The proposed method may offer promising perspectives for fast analyses of biological tissues.
Collapse
Affiliation(s)
- Zhiliang Wei
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, State Key Laboratory for the Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, China
| | | | | | | | | | | | | | | |
Collapse
|
29
|
Tsuda N, Kumadaki S, Higashi C, Ozawa M, Shinozaki M, Kato Y, Hoshida K, Kikuchi S, Nakano Y, Ogawa Y, Furusako S. Intestine-targeted DGAT1 inhibition improves obesity and insulin resistance without skin aberrations in mice. PLoS One 2014; 9:e112027. [PMID: 25405858 PMCID: PMC4236014 DOI: 10.1371/journal.pone.0112027] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Accepted: 10/10/2014] [Indexed: 11/26/2022] Open
Abstract
Objective Diacylglycerol O-acyltransferase 1 (DGAT1) catalyzes the final committed step in triglyceride biosynthesis. DGAT1 null mice are known to be resistant to diet-induced obesity, and more insulin sensitive relative to the wild-type; however, the mice exhibit abnormalities in the skin. This work determined whether the intestine-targeted DGAT1 inhibitor could improve obesity and insulin resistance without skin aberrations in mice. Design and Methods We synthesized 2 DGAT1 inhibitors: Compound A, described in the patent application from the Japan Tobacco, and Compound B (A-922500), reported by Abbott Laboratories. Both compounds were evaluated for inhibitory activities against DGAT1 enzymes and effects on the skin in mice in vivo. Compound B was further investigated for effects on obesity and insulin resistance in diet-induced-obese (DIO) mice. Results The 2 compounds comparably inhibited the DGAT1 enzyme activity and the cellular triglyceride synthesis in vitro, while they showed different distribution patterns in mice in vivo. Compound A, which distributed systemically, caused skin aberrations, while Compound B, which preferentially distributed to the intestine, improved obesity and insulin resistance without skin aberrations in DIO mice. Conclusions Our results suggest that the intestine is the key tissue in which DGAT1 plays a role in promoting obesity and insulin resistance.
Collapse
Affiliation(s)
- Naoto Tsuda
- Discovery Research, Mochida Pharmaceutical Company Limited, Shizuoka, Japan
- Department of Molecular Endocrinology and Metabolism, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
- * E-mail:
| | - Shin Kumadaki
- Discovery Research, Mochida Pharmaceutical Company Limited, Shizuoka, Japan
| | - Chika Higashi
- Discovery Research, Mochida Pharmaceutical Company Limited, Shizuoka, Japan
| | - Makoto Ozawa
- Discovery Research, Mochida Pharmaceutical Company Limited, Shizuoka, Japan
| | - Mikihiko Shinozaki
- Discovery Research, Mochida Pharmaceutical Company Limited, Shizuoka, Japan
| | - Yutaka Kato
- Discovery Research, Mochida Pharmaceutical Company Limited, Shizuoka, Japan
| | - Koutarou Hoshida
- Discovery Research, Mochida Pharmaceutical Company Limited, Shizuoka, Japan
| | - Satomi Kikuchi
- Discovery Research, Mochida Pharmaceutical Company Limited, Shizuoka, Japan
| | - Yoshihisa Nakano
- Discovery Research, Mochida Pharmaceutical Company Limited, Shizuoka, Japan
| | - Yoshihiro Ogawa
- Department of Molecular Endocrinology and Metabolism, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Shoji Furusako
- Discovery Research, Mochida Pharmaceutical Company Limited, Shizuoka, Japan
| |
Collapse
|
30
|
Increased Stearoyl-CoA Desaturase Index and Triglyceride Content in the Liver of Rats after a Single Bout of Swimming Exercise. Biosci Biotechnol Biochem 2014; 76:1350-5. [DOI: 10.1271/bbb.120095] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
|
31
|
Evaluation of dietary effects on hepatic lipids in high fat and placebo diet fed rats by in vivo MRS and LC-MS techniques. PLoS One 2014; 9:e91436. [PMID: 24638096 PMCID: PMC3956606 DOI: 10.1371/journal.pone.0091436] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Accepted: 02/12/2014] [Indexed: 11/25/2022] Open
Abstract
Background & Aims Dietary saturated fatty acids contribute to the development of fatty liver and have pathogenic link to systemic inflammation. We investigated the effects of dietary fat towards the pathogenesis of non-alcoholic fatty liver disease by longitudinal in vivo magnetic resonance spectroscopy (MRS) and in vitro liquid chromatography coupled with mass spectrometry (LC-MS). Methods All measurements were performed on rats fed with high fat diet (HFD) and chow diet for twenty four weeks. Longitudinal MRS measurements were performed at the 12th, 18th and 24th weeks. Liver tissues were analyzed by LC-MS, histology and gene transcription studies after terminal in vivo experiments. Results Liver fat content of HFD rats for all ages was significantly (P<0.05) higher compared to their respective chow diet fed rats. Unsaturation indices estimated from MRS and LC-MS data of chow diet fed rats were significantly higher (P<0.05) than HFD fed rats. The concentration of triglycerides 48∶1, 48∶2, 50∶1, 50∶2, 50∶3, 52∶1, 52∶2, 52∶3, 54∶3 and 54∶2 was significantly higher (P<0.05) in HFD rats. The concentration for some polyunsaturated triglycerides 54∶7, 56∶8, 56∶7, 58∶11, 58∶10, 58∶9, 58∶8 and 60∶10 was significantly higher (P<0.05) in chow diet fed rats compared to HFD rats. Lysophospholipid concentrations including LPC and LPE were higher in HFD rats at 24 weeks indicating the increased risk of diabetes. The expression of CD36, PPARα, SCD1, SREBF1 and UCP2 were significantly upregulated in HFD rats. Conclusions We demonstrated the early changes in saturated and unsaturated lipid composition in fatty liver by in vivo MRS and ex vivo LC-MS. The higher LPC concentration in HFD rats indicated a higher risk of developing diabetes. Early metabolic perturbations causing changes in lipid composition can be evaluated by the unsaturation index and correlated to the non alcoholic fatty liver disease.
Collapse
|
32
|
Ochiai M, Kuroda T, Matsuo T. Increased muscular triglyceride content and hyperglycemia in Goto-Kakizaki rat are decreased by egg white hydrolysate. Int J Food Sci Nutr 2014; 65:495-501. [DOI: 10.3109/09637486.2013.879288] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
|
33
|
Gilbertson TA, Khan NA. Cell signaling mechanisms of oro-gustatory detection of dietary fat: advances and challenges. Prog Lipid Res 2013; 53:82-92. [PMID: 24269201 DOI: 10.1016/j.plipres.2013.11.001] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Accepted: 11/08/2013] [Indexed: 01/19/2023]
Abstract
CD36 and two G-protein coupled receptors (GPCR), i.e., GPR120 and GPR40, have been implicated in the gustatory perception of dietary fats in rodents. These glycoproteins are coupled to increases in free intracellular Ca²⁺ concentrations, [Ca²⁺](i), during their activation by dietary long-chain fatty acids (LCFA). The transient receptor potential type M5 (TRPM5) channel, activated by [Ca²⁺](i), participates in downstream signaling in taste bud cells (TBC). The mice, knocked-out for expression of CD36, GPR120, GPR40 or TRPM5 have a reduced spontaneous preference for fat. The delayed rectifying K⁺ (DRK) channels believed to lie downstream of these receptors are also important players in fat taste transduction. The trigeminal neurons by triggering increases in [Ca²⁺](i) may influence the taste signal to afferent nerve fibers. Why are there so many taste receptor candidates for one taste modality? We discuss the recent advances on the role of CD36, GPR120, GPR40, TRPM5 and DRK channels, in signal transduction in TBC. We shed light on their cross-talk and delineate their roles in obesity as a better understanding of the molecular mechanisms behind their regulation could eventually lead to new strategies to fight against this condition.
Collapse
Affiliation(s)
- Timothy A Gilbertson
- Department of Biology, Utah State University, 5305 Old Main Hill, Logan, UT 84322, USA
| | - Naim A Khan
- INSERM U866, Université de Bourgogne/AgroSup, Dijon 2100, France.
| |
Collapse
|
34
|
Stamatikos AD, Paton CM. Role of stearoyl-CoA desaturase-1 in skeletal muscle function and metabolism. Am J Physiol Endocrinol Metab 2013; 305:E767-75. [PMID: 23941875 DOI: 10.1152/ajpendo.00268.2013] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Stearoyl-CoA desaturase-1 (SCD1) converts saturated fatty acids (SFA) into monounsaturated fatty acids and is necessary for proper liver, adipose tissue, and skeletal muscle lipid metabolism. While there is a wealth of information regarding SCD1 expression in the liver, research on its effect in skeletal muscle is scarce. Furthermore, the majority of information about its role is derived from global knockout mice, which are known to be hypermetabolic and fail to accumulate SCD1's substrate, SFA. We now know that SCD1 expression is important in regulating lipid bilayer fluidity, increasing triglyceride formation, and enabling lipogenesis and may protect against SFA-induced lipotoxicity. Exercise has been shown to increase SCD1 expression, which may contribute to an increase in intramyocellular triglyceride at the expense of free fatty acids and diacylglycerol. This review is intended to define the role of SCD1 in skeletal muscle and discuss the potential benefits of its activity in the context of lipid metabolism, insulin sensitivity, exercise training, and obesity.
Collapse
|
35
|
Close AF, Rouillard C, Buteau J. NR4A orphan nuclear receptors in glucose homeostasis: a minireview. DIABETES & METABOLISM 2013; 39:478-84. [PMID: 24075454 DOI: 10.1016/j.diabet.2013.07.005] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Revised: 07/15/2013] [Accepted: 07/17/2013] [Indexed: 01/23/2023]
Abstract
Type 2 diabetes mellitus is a disorder characterized by insulin resistance and a relative deficit in insulin secretion, both of which result in elevated blood glucose. Understanding the molecular mechanisms underlying the pathophysiology of diabetes could lead to the development of new therapeutic approaches. An ever-growing body of evidence suggests that members of the NR4A family of nuclear receptors could play a pivotal role in glucose homeostasis. This review aims to present and discuss advances so far in the evaluation of the potential role of NR4A in the regulation of glucose homeostasis and the development of type 2 diabetes.
Collapse
Affiliation(s)
- A F Close
- Department of AFNS, University of Alberta and Alberta Diabetes Institute, Li Ka Shing Centre, Edmonton, AB, T6G 2E1, Canada
| | | | | |
Collapse
|
36
|
Macrae K, Stretton C, Lipina C, Blachnio-Zabielska A, Baranowski M, Gorski J, Marley A, Hundal HS. Defining the role of DAG, mitochondrial function, and lipid deposition in palmitate-induced proinflammatory signaling and its counter-modulation by palmitoleate. J Lipid Res 2013; 54:2366-78. [PMID: 23833248 PMCID: PMC3735935 DOI: 10.1194/jlr.m036996] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2013] [Revised: 07/03/2013] [Indexed: 12/27/2022] Open
Abstract
Chronic exposure of skeletal muscle to saturated fatty acids, such as palmitate (C16:0), enhances proinflammatory IKK-NFκB signaling by a mechanism involving the MAP kinase (Raf-MEK-ERK) pathway. Raf activation can be induced by its dissociation from the Raf-kinase inhibitor protein (RKIP) by diacylglycerol (DAG)-sensitive protein kinase C (PKC). However, whether these molecules mediate the proinflammatory action of palmitate, an important precursor for DAG synthesis, is currently unknown. Here, involvement of DAG-sensitive PKCs, RKIP, and the structurally related monounsaturated fatty acid palmitoleate (C16:1) on proinflammatory signaling are investigated. Palmitate, but not palmitoleate, induced phosphorylation/activation of the MEK-ERK-IKK axis and proinflammatory cytokine (IL-6, CINC-1) expression. Palmitate increased intramyocellular DAG and invoked PKC-dependent RKIP(Ser153) phosphorylation, resulting in RKIP-Raf1 dissociation and MEK-ERK signaling. These responses were mimicked by PMA, a DAG mimetic and PKC activator. However, while pharmacological inhibition of PKC suppressed PMA-induced activation of MEK-ERK-IKK signaling, activation by palmitate was upheld, suggesting that DAG-sensitive PKC and RKIP were dispensable for palmitate's proinflammatory action. Strikingly, the proinflammatory effect of palmitate was potently repressed by palmitoleate. This repression was not due to reduced palmitate uptake but linked to increased neutral lipid storage and enhanced cellular oxidative capacity brought about by palmitoleate's ability to restrain palmitate-induced mitochondrial dysfunction.
Collapse
Affiliation(s)
- Katherine Macrae
- Division of Cell Signalling and Immunology, Sir James Black Centre, College of Life Sciences, University of Dundee, Dundee DD1 5EH, United Kingdom
| | - Clare Stretton
- Division of Cell Signalling and Immunology, Sir James Black Centre, College of Life Sciences, University of Dundee, Dundee DD1 5EH, United Kingdom
| | - Christopher Lipina
- Division of Cell Signalling and Immunology, Sir James Black Centre, College of Life Sciences, University of Dundee, Dundee DD1 5EH, United Kingdom
| | | | - Marcin Baranowski
- Department of Physiology, Medical University of Bialystok, 15-222 Bialystok, Poland
| | - Jan Gorski
- Department of Physiology, Medical University of Bialystok, 15-222 Bialystok, Poland
| | - Anna Marley
- Department of Physiology, AstraZeneca, Cheshire SK10 4TG, United Kingdom
| | - Harinder S. Hundal
- Division of Cell Signalling and Immunology, Sir James Black Centre, College of Life Sciences, University of Dundee, Dundee DD1 5EH, United Kingdom
| |
Collapse
|
37
|
Effects of long-term administration of saturated and n-3 fatty acid-rich diets on lipid utilisation and oxidative stress in rat liver and muscle tissues. Br J Nutr 2013; 110:1789-802. [DOI: 10.1017/s0007114513001311] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The incidence of metabolic syndrome components including obesity, lipid deregulation, insulin resistance (IR) and non-alcoholic fatty liver disease is increasing rapidly in wealthy societies. The present study was designed to determine the effect of different nutritional lipid patterns (quantity and quality) on lipid utilisation and oxidative stress in the liver and muscle of rats in an integrated fashion. A total of forty-eight Wistar male rats were fed for 12 weeks with a mixed, lard or fish-oil diet, containing either 50 or 300 g lipid/kg. Rats developed liver steatosis associated with moderate liver injury when fed the 30 % lipid diets, in spite of the absence of overt obesity or IR, except when fed the lard 30 % lipid diet. The intake of the 30 % lipid diets decreased hepatic lipogenesis and mitochondriogenesis and increased lipid peroxidation and protein oxidation. Surprisingly, muscle lipid content was not modified whatever the administered diet. The intake of the 30 % lipid diets increased the muscle protein expression of fatty acid (FA) translocase/cluster of differentiation 36 (FAT/CD36), PPARγ co-activator 1α (PGC-1α) and muscle carnitine palmitoyltransferase 1 (m-CPT1), reflecting increased FA transport in the muscle associated with increased oxidative metabolism. The lard 30 % lipid diet led to IR without modifying the muscle lipid content. The fish-oil 30 % lipid diet failed to prevent the development of hepatic steatosis and made the tissues more prone to oxidation. Overall, the present study suggests that the FA composition of muscle is more important than lipid accumulation itself in the modulation of insulin sensitivity, and indicates that precaution should be taken when advising an unphysiologically high (pharmacological) supplementation with long-chain n-3 PUFA.
Collapse
|
38
|
Wone BWM, Donovan ER, Cushman JC, Hayes JP. Metabolic rates associated with membrane fatty acids in mice selected for increased maximal metabolic rate. Comp Biochem Physiol A Mol Integr Physiol 2013; 165:70-8. [PMID: 23422919 DOI: 10.1016/j.cbpa.2013.02.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2012] [Revised: 02/11/2013] [Accepted: 02/12/2013] [Indexed: 12/19/2022]
Abstract
Aerobic metabolism of vertebrates is linked to membrane fatty acid (FA) composition. Although the membrane pacemaker hypothesis posits that desaturation of FAs accounts for variation in resting or basal metabolic rate (BMR), little is known about the FA profiles that underpin variation in maximal metabolic rate (MMR). We examined membrane FA composition of liver and skeletal muscle in mice after seven generations of selection for increased MMR. In both liver and skeletal muscle, unsaturation index did not differ between control and high-MMR mice. We also examined membrane FA composition at the individual-level of variation. In liver, 18:0, 20:3 n-6, 20:4 n-6, and 22:6 n-3 FAs were significant predictors of MMR. In gastrocnemius muscle, 18:2 n-6, 20:4 n-6, and 22:6 n-3 FAs were significant predictors of MMR. In addition, muscle 16:1 n-7, 18:1 n-9, and 22:5 n-3 FAs were significant predictors of BMR, whereas no liver FAs were significant predictors of BMR. Our findings indicate that (i) individual variation in MMR and BMR appears to be linked to membrane FA composition in the skeletal muscle and liver, and (ii) FAs that differ between selected and control lines are involved in pathways that can affect MMR or BMR.
Collapse
Affiliation(s)
- Bernard W M Wone
- Program in Ecology, Evolution, and Conservation Biology, University of Nevada, Reno, NV 89557-0314, USA.
| | | | | | | |
Collapse
|
39
|
Ochiai M, Matsuo T. Pioglitazone-Induced Increase in the Stearoyl-CoA Desaturation Index and Fat Accumulation in Rat Muscles Are Not Related to Lipoprotein Lipase Activity. J Oleo Sci 2013; 62:745-54. [DOI: 10.5650/jos.62.745] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
|
40
|
Kunešová M, Hlavatý P, Tvrzická E, Staňková B, Kalousková P, Viguerie N, Larsen TM, van Baak MA, Jebb SA, Martinez JA, Pfeiffer AFH, Kafatos A, Handjieva-Darlenska T, Hill M, Langin D, Zák A, Astrup A, Saris WHM. Fatty acid composition of adipose tissue triglycerides after weight loss and weight maintenance: the DIOGENES study. Physiol Res 2012; 61:597-607. [PMID: 23098653 DOI: 10.33549/physiolres.932414] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Fatty acid composition of adipose tissue changes with weight loss. Palmitoleic acid as a possible marker of endogenous lipogenesis or its functions as a lipokine are under debate. Objective was to assess the predictive role of adipose triglycerides fatty acids in weight maintenance in participants of the DIOGENES dietary intervention study. After an 8-week low calorie diet (LCD) subjects with > 8 % weight loss were randomized to 5 ad libitum weight maintenance diets for 6 months: low protein (P)/low glycemic index (GI) (LP/LGI), low P/high GI (LP/HGI), high P/low GI (HP/LGI), high P/high GI (HP/HGI), and a control diet. Fatty acid composition in adipose tissue triglycerides was determined by gas chromatography in 195 subjects before the LCD (baseline), after LCD and weight maintenance. Weight change after the maintenance phase was positively correlated with baseline adipose palmitoleic (16:1n-7), myristoleic (14:1n-5) and trans-palmitoleic acid (16:1n-7t). Negative correlation was found with baseline oleic acid (18:1n-9). Lower baseline monounsaturated fatty acids (14:1n-5, 16:1n-7 and trans 16:1n-7) in adipose tissue triglycerides predict better weight maintenance. Lower oleic acid predicts lower weight decrease. These findings suggest a specific role of monounsaturated fatty acids in weight management and as weight change predictors.
Collapse
Affiliation(s)
- M Kunešová
- Obesity Management Centre, Institute of Endocrinology, Prague, Czech Republic.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
41
|
Gniuli D, Rosa G, Manco M, Scarfone A, Vega N, Greco AV, Castagneto M, Vidal H, Mingrone G. Changes in Fat Mass InfluenceSREBP-1candUCP-2Gene Expression in Formerly Obese Subjects. ACTA ACUST UNITED AC 2012; 13:567-73. [PMID: 15833942 DOI: 10.1038/oby.2005.60] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
OBJECTIVE To investigate the effect of fat mass (FM) reduction on adipose tissue gene expression in terms of lipid synthesis [sterol regulatory binding protein 1c (SREBP-1c)] and lipid oxidation [uncoupling protein 2 (UCP-2)] 2 years after lipid malabsorption and to assess the influence of lipid malabsorption on fat-free mass (FFM) maintenance evaluating the expression of genes related to glycolysis [hexokinase (HKII)] and glucose storage [glycogen synthase (GS)]. RESEARCH METHOD AND PROCEDURES SREBP-1c, UCP-2, HKII, and GS mRNA expression were studied by reverse transcriptase-competitive polymerase chain reaction in 10 massively obese subjects before and 2 years after bilio-pancreatic diversion (BPD). Body composition was assessed by isotopic dilution method and insulin sensitivity by euglycemic-hyperinsulinemic clamp. RESULTS FM decrease was approximately 60%, whereas FFM remained at normal physiological levels. In adipose tissue, SREBP-1c mRNA reduction (-39%, p < 0.005) was related only to FM changes after BPD, and UCP-2 decrease (-37%, p < 0.05) was dependent on free fatty acid (FFA) changes. No significant variations were observed in HKII and GS gene expression in skeletal muscle. DISCUSSION Lipid malabsorption induced by BPD altered the expression of genes involved in glucose and lipid metabolism, with different consequences on FM and FFM. The degree of FM loss seems to interfere with SREBP-1c gene suppression to preserve an adequate amount of fat storage, in accordance with the thrifty genotype hypothesis. The reduction of FFAs induced by BPD acts in inhibiting FFA transportation to the mitochondria (UCP-2), contributing to the decreased lipid oxidation inside the adipose tissue.
Collapse
Affiliation(s)
- Donatella Gniuli
- Department of Internal Medicine, Catholic University of the Sacred Heart, Rome, Italy.
| | | | | | | | | | | | | | | | | |
Collapse
|
42
|
Manco M, Calvani M, Nanni G, Greco AV, Iaconelli A, Gasbarrini G, Castagneto M, Mingrone G. Low 25-Hydroxyvitamin D Does Not Affect Insulin Sensitivity in Obesity after Bariatric Surgery. ACTA ACUST UNITED AC 2012; 13:1692-700. [PMID: 16286516 DOI: 10.1038/oby.2005.207] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
OBJECTIVE A positive correlation between levels of 25-hydroxyvitamin D [25(OH)D] and insulin sensitivity has been shown in healthy subjects. We aimed to test the hypothesis that concentration of 25(OH)D influences insulin sensitivity in obesity before and after weight loss. RESEARCH METHODS AND PROCEDURES We investigated the relation between serum 25(OH)D and insulin sensitivity (estimated by euglycemic-hyperinsulinemic clamp) in 116 obese women (BMI > or = 40 kg/m2) evaluated before and 5 and 10 years after biliopancreatic diversion (BPD). Body composition was estimated by the isotope dilution method. RESULTS Prevalence of hypovitaminosis D was 76% in the obese status and 91% and 89% at 5 and 10 years after BPD, respectively, despite ergocalciferol supplementation. 25(OH)D concentration decreased from 39.2 +/- 22.3 in obesity (p = 0.0001) to 27.4 +/- 16.4 and 25.1 +/- 13.9 nM 5 and 10 years after BPD, respectively. Whole-body glucose uptake increased from 24.27 +/- 4.44 at the baseline to 57.29 +/- 11.56 and 57.71 +/- 8.41 mumol/kg(fat free mass) per minute 5 and 10 years after BPD, respectively (p = 0.0001). Predictor of 25(OH)D was fat mass (R2 = 0.26, p = 0.0001 in obesity; R2 = 0.20, p = 0.02 after BPD). Parathormone correlated with fat mass (R2 = 0.19; p = 0.0001) and BMI (R2 = 0.053; p = 0.01) and inversely with M value (R2 = 0.16; p = 0.0001), but only in obese subjects. DISCUSSION A high prevalence of hypovitaminosis D was observed in morbid obesity both before and after BPD. Low 25(OH)D did not necessarily imply increased insulin resistance after BPD, a condition where, probably, more powerful determinants of insulin sensitivity overcome the low circulating 25(OH)D levels. However, the present data cannot exclude some kind of influence of vitamin D status on glucose and insulin metabolism.
Collapse
Affiliation(s)
- Melania Manco
- Department of Internal Medicine, Catholic University, School of Medicine, 484 Pineta Sacchetti, 00168 Rome, Italy.
| | | | | | | | | | | | | | | |
Collapse
|
43
|
Chabowski A, Zendzian-Piotrowska M, Nawrocki A, Górski J. Not only accumulation, but also saturation status of intramuscular lipids is significantly affected by PPARγ activation. Acta Physiol (Oxf) 2012; 205:145-58. [PMID: 22023892 DOI: 10.1111/j.1748-1716.2011.02380.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
AIM Intramuscular lipid accumulation has been associated with insulin resistance, and after thiazolidinediones (TZD) treatment, it was shown to be reduced in some, but not all, studies. This work was undertaken to investigate the relationships between intramuscular lipids [free fatty acids (FFA), diacylglycerols (DAG), triacylglycerol (TAG) and phospholipids] and plasmalemmal expression of fatty acid (FA) transporter [FAT/CD36 and FABPpm] in the muscles of varying oxidative capacity, after peroxisome proliferator-activated receptors gamma (PPARγ) activation (rosiglitazone) in an animal model of high-fat-diet-induced insulin resistance. Endurance training was also included to further explore the differences in these relationships. METHODS We have used gas liquid chromatography to estimate FA content and composition in each lipid fraction. For sarcolemmal expression of FA transporters, subfractionation of skeletal muscles with subsequent western blot technique was applied. RESULTS High-fat diet induced intramuscular accumulation of FFA, DAG and TAG, irrespective of muscle's fibre composition. PPARγ activation (rosiglitazone) and, to a lesser extent, endurance training further increased TAG accumulation, while it reduced DAG in oxidative muscles (soleus and red gastrocnemius). Aforementioned interventions increased also sarcolemmal FAT/CD36 and FABPpm expressions in particular muscles. Irrespective of diet, rosiglitazone and exercise decreased significantly FA saturation status favouring proportionate enhancement in monounsaturated FA (rosiglitazone) or polyunsaturated FAs (endurance training). CONCLUSION These findings support the conclusion that not only the change in total lipid content (DAG and TAG), but also FA composition is affected by rosiglitazone in an animal model of high-fat-diet-induced insulin resistance.
Collapse
Affiliation(s)
- A Chabowski
- Department of Physiology, Medical University of Bialystok, Poland.
| | | | | | | |
Collapse
|
44
|
Effects of polymorphisms in nucleotide-binding oligomerization domains 1 and 2 on biomarkers of the metabolic syndrome and type II diabetes. GENES AND NUTRITION 2012; 7:427-35. [PMID: 22367890 DOI: 10.1007/s12263-012-0287-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2011] [Accepted: 02/07/2012] [Indexed: 01/01/2023]
Abstract
The innate immune receptor toll-like receptor 4 (TLR4) has been implicated in mediating some of the effects of dietary lipids on inflammation and type 2 diabetes (T2D). Similar to TLR4, the nucleotide-binding oligomerization domains (Nods) 1 and 2 are also proteins of innate immunity, which can respond to lipids and initiate pro-inflammatory signalling that plays a role in the aetiology of T2D. The objective was to determine the effect of Nod1 (Glu266Lys) and Nod2 (Ser268Pro) genotypes on factors associated with the metabolic syndrome (MetS), and whether they modify the association between dietary lipids and biomarkers of the MetS. Men and women (n = 998) between the ages of 20-29 years were genotyped for both polymorphisms, completed a one-month, semiquantitative food frequency questionnaire and provided a fasting blood sample. The Glu266Lys polymorphism in Nod1 was not associated with any of the biomarkers of the MetS, but modified the association between dietary saturated fat (SFA) and insulin sensitivity, as measured by HOMA-IR (p for interaction = 0.04). Individuals with the Glu/Glu or Glu/Lys genotype showed no significant relationship between dietary SFA and HOMA-IR (β = -0.002 ± 0.006, p = 0.77; and β = -0.003 ± 0.006, p = 0.61), while those with the Lys/Lys genotype showed a positive association (β = 0.033 ± 0.02, p = 0.03). The Nod2 Ser268Pro polymorphism was not associated with components of the MetS and did not modify the relationship between dietary lipid intake and the biomarkers of MetS. In summary, the Nod1 Glu266Lys polymorphism modifies the relationship between dietary SFA intake and HOMA-IR, suggesting that Nod1 may act as an intracellular lipid sensor affecting insulin sensitivity.
Collapse
|
45
|
Hang TC, Lauffenburger DA, Griffith LG, Stolz DB. Lipids promote survival, proliferation, and maintenance of differentiation of rat liver sinusoidal endothelial cells in vitro. Am J Physiol Gastrointest Liver Physiol 2012; 302:G375-88. [PMID: 22075778 PMCID: PMC3287397 DOI: 10.1152/ajpgi.00288.2011] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Primary rat liver sinusoidal endothelial cells (LSEC) are difficult to maintain in a differentiated state in culture for scientific studies or technological applications. Relatively little is known about molecular regulatory processes that affect LSEC differentiation because of this inability to maintain cellular viability and proper phenotypic characteristics for extended times in vitro, given that LSEC typically undergo death and detachment around 48-72 h even when treated with VEGF. We demonstrate that particular lipid supplements added to serum-free, VEGF-containing medium increase primary rat liver LSEC viability and maintain differentiation. Addition of a defined lipid combination, or even oleic acid (OA) alone, promotes LSEC survival beyond 72 h and proliferation to confluency. Moreover, assessment of LSEC cultures for endocytic function, CD32b surface expression, and exhibition of fenestrae showed that these differentiation characteristics were maintained when lipids were included in the medium. With respect to the underlying regulatory pathways, we found lipid supplement-enhanced phosphatidylinositol 3-kinase and MAPK signaling to be critical for ensuring LSEC function in a temporally dependent manner. Inhibition of Akt activity before 72 h prevents growth of SEC, whereas MEK inhibition past 72 h prevents survival and proliferation. Our findings indicate that OA and lipids modulate Akt/PKB signaling early in culture to mediate survival, followed by a switch to a dependence on ERK signaling pathways to maintain viability and induce proliferation after 72 h. We conclude that free fatty acids can support maintenance of liver LSEC cultures in vitro; key regulatory pathways involved include early Akt signaling followed by ERK signaling.
Collapse
Affiliation(s)
- Ta-Chun Hang
- 1Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts; and
| | - Douglas A. Lauffenburger
- 1Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts; and
| | - Linda G. Griffith
- 1Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts; and
| | - Donna B. Stolz
- 2Department of Cell Biology & Physiology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania
| |
Collapse
|
46
|
Habegger KM, Penque BA, Sealls W, Tackett L, Bell LN, Blue EK, Gallagher PJ, Sturek M, Alloosh MA, Steinberg HO, Considine RV, Elmendorf JS. Fat-induced membrane cholesterol accrual provokes cortical filamentous actin destabilisation and glucose transport dysfunction in skeletal muscle. Diabetologia 2012; 55:457-67. [PMID: 22002007 PMCID: PMC3245823 DOI: 10.1007/s00125-011-2334-y] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2009] [Accepted: 09/19/2011] [Indexed: 11/26/2022]
Abstract
AIMS/HYPOTHESIS Diminished cortical filamentous actin (F-actin) has been implicated in skeletal muscle insulin resistance, yet the mechanism(s) is unknown. Here we tested the hypothesis that changes in membrane cholesterol could be a causative factor, as organised F-actin structure emanates from cholesterol-enriched raft microdomains at the plasma membrane. METHODS Skeletal muscle samples from high-fat-fed animals and insulin-sensitive and insulin-resistant human participants were evaluated. The study also used L6 myotubes to directly determine the impact of fatty acids (FAs) on membrane/cytoskeletal variables and insulin action. RESULTS High-fat-fed insulin-resistant animals displayed elevated levels of membrane cholesterol and reduced F-actin structure compared with normal chow-fed animals. Moreover, human muscle biopsies revealed an inverse correlation between membrane cholesterol and whole-body glucose disposal. Palmitate-induced insulin-resistant myotubes displayed membrane cholesterol accrual and F-actin loss. Cholesterol lowering protected against the palmitate-induced defects, whereas characteristically measured defects in insulin signalling were not corrected. Conversely, cholesterol loading of L6 myotube membranes provoked a palmitate-like cytoskeletal/GLUT4 derangement. Mechanistically, we observed a palmitate-induced increase in O-linked glycosylation, an end-product of the hexosamine biosynthesis pathway (HBP). Consistent with HBP activity affecting the transcription of various genes, we observed an increase in Hmgcr, a gene that encodes 3-hydroxy-3-methyl-glutaryl coenzyme A reductase, the rate-limiting enzyme in cholesterol synthesis. In line with increased HBP activity transcriptionally provoking a membrane cholesterol-based insulin-resistant state, HBP inhibition attenuated Hmgcr expression and prevented membrane cholesterol accrual, F-actin loss and GLUT4/glucose transport dysfunction. CONCLUSIONS/INTERPRETATION Our results suggest a novel cholesterolgenic-based mechanism of FA-induced membrane/cytoskeletal disorder and insulin resistance.
Collapse
Affiliation(s)
- K. M. Habegger
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, VanNuys Medical Science Building Rm 308A, 635 Barnhill Drive, Indianapolis, IN 46202-5120 USA
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN USA
- Indiana University School of Medicine Center for Diabetes Research, Indianapolis, IN USA
- Indiana University School of Medicine Center for Membrane Biosciences, Indianapolis, IN USA
| | - B. A. Penque
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, VanNuys Medical Science Building Rm 308A, 635 Barnhill Drive, Indianapolis, IN 46202-5120 USA
- Indiana University School of Medicine Center for Diabetes Research, Indianapolis, IN USA
- Indiana University School of Medicine Center for Membrane Biosciences, Indianapolis, IN USA
| | - W. Sealls
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, VanNuys Medical Science Building Rm 308A, 635 Barnhill Drive, Indianapolis, IN 46202-5120 USA
- Indiana University School of Medicine Center for Diabetes Research, Indianapolis, IN USA
- Indiana University School of Medicine Center for Membrane Biosciences, Indianapolis, IN USA
- Indiana University School of Medicine Center for Vascular Biology and Medicine, Indianapolis, IN USA
| | - L. Tackett
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, VanNuys Medical Science Building Rm 308A, 635 Barnhill Drive, Indianapolis, IN 46202-5120 USA
| | - L. N. Bell
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, VanNuys Medical Science Building Rm 308A, 635 Barnhill Drive, Indianapolis, IN 46202-5120 USA
- Indiana University School of Medicine Center for Diabetes Research, Indianapolis, IN USA
- Department of Medicine, Division of Endocrinology and Metabolism, Indiana University School of Medicine, Indianapolis, IN USA
| | - E. K. Blue
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, VanNuys Medical Science Building Rm 308A, 635 Barnhill Drive, Indianapolis, IN 46202-5120 USA
- Indiana University School of Medicine Center for Diabetes Research, Indianapolis, IN USA
| | - P. J. Gallagher
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, VanNuys Medical Science Building Rm 308A, 635 Barnhill Drive, Indianapolis, IN 46202-5120 USA
- Indiana University School of Medicine Center for Diabetes Research, Indianapolis, IN USA
| | - M. Sturek
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, VanNuys Medical Science Building Rm 308A, 635 Barnhill Drive, Indianapolis, IN 46202-5120 USA
- Indiana University School of Medicine Center for Diabetes Research, Indianapolis, IN USA
- Indiana University School of Medicine Center for Vascular Biology and Medicine, Indianapolis, IN USA
| | - M. A. Alloosh
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, VanNuys Medical Science Building Rm 308A, 635 Barnhill Drive, Indianapolis, IN 46202-5120 USA
- Indiana University School of Medicine Center for Diabetes Research, Indianapolis, IN USA
- Indiana University School of Medicine Center for Vascular Biology and Medicine, Indianapolis, IN USA
| | | | - R. V. Considine
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, VanNuys Medical Science Building Rm 308A, 635 Barnhill Drive, Indianapolis, IN 46202-5120 USA
- Indiana University School of Medicine Center for Diabetes Research, Indianapolis, IN USA
- Department of Medicine, Division of Endocrinology and Metabolism, Indiana University School of Medicine, Indianapolis, IN USA
| | - J. S. Elmendorf
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, VanNuys Medical Science Building Rm 308A, 635 Barnhill Drive, Indianapolis, IN 46202-5120 USA
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN USA
- Indiana University School of Medicine Center for Diabetes Research, Indianapolis, IN USA
- Indiana University School of Medicine Center for Membrane Biosciences, Indianapolis, IN USA
- Indiana University School of Medicine Center for Vascular Biology and Medicine, Indianapolis, IN USA
| |
Collapse
|
47
|
Mai K, Andres J, Bobbert T, Assmann A, Biedasek K, Diederich S, Graham I, Larson TR, Pfeiffer AFH, Spranger J. Rosiglitazone increases fatty acid Δ9-desaturation and decreases elongase activity index in human skeletal muscle in vivo. Metabolism 2012; 61:108-16. [PMID: 21741058 DOI: 10.1016/j.metabol.2011.05.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2010] [Revised: 05/18/2011] [Accepted: 05/19/2011] [Indexed: 11/26/2022]
Abstract
The ratio of unsaturated to saturated long-chain fatty acids (LC-FAs) in skeletal muscle has been associated with insulin resistance. Some animal data suggest a modulatory effect of peroxisome proliferator receptor γ (PPARγ) stimulation on stearoyl-CoA desaturase 1 (SCD1) and LC-FA composition in skeletal muscle, but human data are rare. We here investigate whether treatment with a PPARγ agonist affects myocellular SCD1 expression and modulates the intramyocellular fatty acid profile in individuals with impaired glucose tolerance. Muscle biopsies and hyperinsulinemic-euglycemic clamps were performed in 7 men before and after 8 weeks of rosiglitazone treatment. Intramyocellular saturated, monounsaturated, and polyunsaturated intramuscular fatty acid profiles were measured by gas chromatography. Effects on SCD1 messenger RNA expression were analyzed in C2C12 cells and in human biopsies before and after rosiglitazone treatment. As expected, treatment with the PPARγ activator rosiglitazone improved insulin sensitivity in humans. Myocellular SCD1 messenger RNA expression was increased in human biopsies and C2C12 cells. Although the total content of myocellular LC-FA was unchanged, a relative shift from saturated LC-FAs to unsaturated LC-FAs was observed in human biopsies. Particularly, the amount of stearate was reduced, whereas the amounts of palmitoleate as well as oleate and vaccenate were increased, after rosiglitazone therapy. These changes resulted in an increased fatty acid Δ9-desaturation index (16:1/16:0 and 18:1/18:0) in skeletal muscle and a decreased elongase activity index (18:0/16:0). The PPARγ associated phenotypes may be partially explained by an increased Δ9-desaturation and a decreased elongase activity of skeletal muscle.
Collapse
Affiliation(s)
- Knut Mai
- Department of Endocrinology, Diabetes and Nutrition, Charite-University Medicine Berlin, Campus Benjamin Franklin, Berlin, Germany
| | | | | | | | | | | | | | | | | | | |
Collapse
|
48
|
Thoresen GH, Hessvik NP, Bakke SS, Aas V, Rustan AC. Metabolic switching of human skeletal muscle cells in vitro. Prostaglandins Leukot Essent Fatty Acids 2011; 85:227-34. [PMID: 21549583 DOI: 10.1016/j.plefa.2011.04.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
In this review we will focus on external factors that may modify energy metabolism in human skeletal muscle cells (myotubes) and the ability of the myotubes to switch between lipid and glucose oxidation. We describe the metabolic parameters suppressibility, adaptability and substrate-regulated flexibility, and show the influence of nutrients such as fatty acids and glucose (chronic hyperglycemia), and some pharmacological agents modifying nuclear receptors (PPAR and LXR), on these parameters in human myotubes. Possible cellular mechanisms for changes in these parameters will also be highlighted.
Collapse
Affiliation(s)
- G H Thoresen
- Department of Pharmaceutical Biosciences, School of Pharmacy, University of Oslo, Oslo, Norway
| | | | | | | | | |
Collapse
|
49
|
Bydder M, Girard O, Hamilton G. Mapping the double bonds in triglycerides. Magn Reson Imaging 2011; 29:1041-6. [DOI: 10.1016/j.mri.2011.07.004] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2010] [Revised: 05/24/2011] [Accepted: 07/06/2011] [Indexed: 11/27/2022]
|
50
|
Brands M, Hoeks J, Sauerwein HP, Ackermans MT, Ouwens M, Lammers NM, van der Plas MN, Schrauwen P, Groen AK, Serlie MJ. Short-term increase of plasma free fatty acids does not interfere with intrinsic mitochondrial function in healthy young men. Metabolism 2011; 60:1398-405. [PMID: 21489571 DOI: 10.1016/j.metabol.2011.02.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2010] [Revised: 02/02/2011] [Accepted: 02/09/2011] [Indexed: 11/21/2022]
Abstract
Free fatty acid (FFA)- and obesity-induced insulin resistance has been associated with disturbed mitochondrial function. Elevated plasma FFA can impair insulin-induced increase of adenosine triphosphate synthesis and downregulate the expression of genes important in the biogenesis of mitochondria in human skeletal muscle. Whether FAs have a direct effect on intrinsic mitochondrial capacity remains to be established. Therefore, we measured ex vivo mitochondrial respiratory capacity in human skeletal muscle after exposure to hyperinsulinemia and high levels of plasma FFA. Nine healthy lean men were studied during a 6-hour hyperinsulinemic (600 pmol/L) euglycemic clamp with concomitant infusion of Intralipid (Fresensius Kabi Nederland, Den Bosch, the Netherlands) (FFA clamped at 0.5 mmol/L) or saline. Mitochondrial respiratory capacity was measured by high-resolution respirometry in permeabilized muscle fibers using an Oxygraph (OROBOROS Instruments, Innsbruck, Austria). Each participant served as his own control. Peripheral glucose uptake (rate of disappearance) was significantly lower during infusion of the lipid emulsion compared with the control saline infusion (68 μmol/kg·min [saline] vs 40 μmol/kg·min [lipid], P = .008). However, adenosine diphosphate-stimulated and maximal carbonylcyanide-4-(trifluoromethoxy)-phenylhydrazone-stimulated uncoupled respiration rates were not different in permeabilized skeletal muscle fibers after exposure to high levels of FFA compared with the control condition. We conclude that short-term elevation of FFA within the physiological range induces insulin resistance but does not affect intrinsic mitochondrial capacity in skeletal muscle in humans.
Collapse
MESH Headings
- Adult
- Biopsy
- Blood Glucose/metabolism
- Cell Respiration/drug effects
- Cell Respiration/physiology
- Fatty Acids, Nonesterified/blood
- Fatty Acids, Nonesterified/metabolism
- Fatty Acids, Nonesterified/pharmacology
- Glucose Clamp Technique
- Health
- Humans
- Insulin/blood
- Insulin Resistance/physiology
- Male
- Mitochondria, Muscle/drug effects
- Mitochondria, Muscle/metabolism
- Mitochondria, Muscle/physiology
- Muscle, Skeletal/drug effects
- Muscle, Skeletal/metabolism
- Muscle, Skeletal/pathology
- Muscle, Skeletal/physiology
- Oxidation-Reduction/drug effects
- Time Factors
- Young Adult
Collapse
Affiliation(s)
- Myrte Brands
- Department of Endocrinology and Metabolism, Academic Medical Center Amsterdam, 1105 AZ Amsterdam, The Netherlands.
| | | | | | | | | | | | | | | | | | | |
Collapse
|